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The examination of biophysical parameters of skin (transepidermal water loss, skin hydration and pH value) in different body regions of normal cats of both sexes

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The purpose of this study was to evaluate transepidermal water loss (TEWL), skin hydration and skin pH in normal cats. Twenty shorthaired European cats of both sexes were examined in the study. Measurements were taken from five different sites: the lumbar region, the axillary fossa, the inguinal region, the ventral abdominal region and the left thoracic region. In each of the regions, TEWL, skin hydration and skin pH were measured. The highest TEWL value was observed in the axillary fossa (18.22g/h/m(2)) and the lowest in the lumbar region (10.53g/h/m(2)). The highest skin hydration was found in the inguinal region (18.29CU) and the lowest in the lumbar region (4.62CU). The highest skin pH was observed in the inguinal region (6.64) and the lowest in the lumbar region (6.39). Statistically significant differences in TEWL were observed between the lumbar region and the left side of the thorax region (P=0.016), the axillary fossa (P=0.0004), the ventral region (P=0.005), and the inguinal region (P=0.009). There were significant differences in skin hydration between the lumbar region and the left thorax (P=0.000003), the axillary fossa (P=0.002), the ventral abdomen (P=0.03), and the inguinal region (P=0.0003) as well as between the thorax and the ventral abdomen (P=0.005). TEWL was higher in females (15g/h/m(2)) than in males (4.57g/h/m(2)). Skin hydration was higher in females (13.89CU) than in males (12.28CU). Significant differences were not found between males and females for TEWL and skin hydration. Skin pH was higher in males (6.94) than in females (6.54), which was significant (P=0.004).
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The examination of biophysical parameters of skin
(transepidermal water loss, skin hydration and pH
value) in different body regions of normal cats of
both sexes
Marcin P Szczepanik PhD*, Piotr M Wilkołek PhD, Łukasz R Adamek MVD,
Zbigniew JH Pomorski PhD
Subdepartment of Clinical
Diagnostics and Veterinary
Dermatology, University of Life
Sciences in Lublin, Gleboka 30,
Poland
The purpose of this study was to evaluate transepidermal water loss (TEWL),
skin hydration and skin pH in normal cats. Twenty shorthaired European cats of
both sexes were examined in the study. Measurements were taken from five
different sites: the lumbar region, the axillary fossa, the inguinal region, the
ventral abdominal region and the left thoracic region. In each of the regions,
TEWL, skin hydration and skin pH were measured. The highest TEWL value
was observed in the axillary fossa (18.22 g/h/m
2
) and the lowest in the lumbar
region (10.53 g/h/m
2
). The highest skin hydration was found in the inguinal
region (18.29 CU) and the lowest in the lumbar region (4.62 CU). The highest
skin pH was observed in the inguinal region (6.64) and the lowest in the lumbar
region (6.39). Statistically significant differences in TEWL were observed
between the lumbar region and the left side of the thorax region (P¼0.016), the
axillary fossa (P¼0.0004), the ventral region (P¼0.005), and the inguinal region
(P¼0.009). There were significant differences in skin hydration between the
lumbar region and the left thorax (P¼0.000003), the axillary fossa (P¼0.002),
the ventral abdomen (P¼0.03), and the inguinal region (P¼0.0003) as well as
between the thorax and the ventral abdomen (P¼0.005). TEWL was higher in
females (15 g/h/m
2
) than in males (4.57 g/h/m
2
). Skin hydration was higher in
females (13.89 CU) than in males (12.28 CU). Significant differences were not
found between males and females for TEWL and skin hydration. Skin pH was
higher in males (6.94) than in females (6.54), which was significant (P¼0.004).
Date accepted: 4 November 2010 Crown Copyright Ó2010 Published by Elsevier Ltd on behalf of
ISFM and AAFP. All rights reserved.
Avariety of measurements of biophysical
parameters, such as transepidermal water
loss (TEWL), skin hydration (corneometry)
and skin pH have recently been used to complement
other methods of examining skin. These methods are
validated
1
in human medicine and used, among
others, to examine skin in atopic dermatitis,
2e6
in or-
der to evaluate the effectiveness of locally applied
treatment,
7e9
and in contact dermatitis.
10
These pa-
rameters have also been studied in veterinary medi-
cine, most commonly in dogs.
11e20
Among the aforementioned parameters, TEWL has
been examined most frequently. TEWL is defined as
outward diffusion of water through the skin into the
comparatively low relative humidity of the
atmosphere. Tewametry measures TEWL and de-
scribes the skin’s ability to retain water. This non-inva-
sive technique is widely held to be a sensitive
indicator of impaired barrier function of the skin
and epidermal damage.
1,3,11,21e23
Increased TEWL
has been observed in people
2e5
and dogs
21,22
with
atopic dermatitis. In atopic dogs there are ultrastruc-
tural changes in the stratum corneum, including ab-
normalities in lipid lamellae organisation and wider
intracellular spaces.
24
These changes in barrier func-
tion are responsible for increased permeability for en-
vironmental allergens and allow an enhanced
penetration of them, increasing the risk for
sensitisation.
24
Corneometry, the evaluation of skin hydration, is
based on measures of electric capacitance of the stra-
tum corneum and indicates the relative hydration of
*Corresponding author. E-mail: kryll@poczta.onet.pl
Journal of Feline Medicine and Surgery (2011) 13, 224e230
doi:10.1016/j.jfms.2010.11.003
1098-612X/10/040224+07 $36.00/0 Crown Copyright Ó2010 Published by Elsevier Ltd on behalf of
ISFM and AAFP. All rights reserved.
Author's personal copy
this epidermal layer. This method determines the wa-
ter content of the outer layer of the stratum corneum
at the depth of 10e20 mmto60e100 mm.
1,5,16
A decrease of the value of this parameter has been
confirmed in atopic dermatitis in humans.
5
Changes in skin pH have been demonstrated in
people, with an increase in pH observed in atopic der-
matitis, seborrheic dermatitis, acne, ichthyosis, contact
dermatitis and Candida albicans infections.
4,14,25
In-
creases in skin pH have also been demonstrated in
dogs with pyoderma.
26
Multiple factors such as age, sex, breed, and ana-
tomical site influencing the value of TEWL, skin hy-
dration and skin pH have been examined in dogs as
well as in humans.
11,14e18,21,27
With the exception of skin pH,
28
no studies have in-
vestigated TEWL or skin hydration in cats. The pur-
pose of this study was to examine these biophysical
parameters in normal cats of both sexes in different
body sites.
Materials and methods
Twenty shorthaired European cats of both sexes
(12 females, including seven spayed, and eight males,
including three castrated), ranging in age from 6
months to 6 years (mean age 26 months) were in-
cluded in the study. The cats were privately owned.
All owners were informed about the details of the ex-
amination and signed permission forms to enrol their
pets in the study. The study was approved by the
University Ethics Commission (resolution number
32/2009 21.04.2009). All cats were given a complete
physical and dermatological examination before tak-
ing the measurements. Only clinically healthy ani-
mals with no history of skin or systemic disease
were included in the study. The animals were accli-
matised in the test room 1 h before the measurements
were taken. The temperature in the room ranged
from 25e28C and the relative humidity from
40e65%. The examination was performed from
March to November 2009. The temperature and rela-
tive humidity were similar to those reported by other
authors.
11,16,19,21
Measurements were taken from five different sites:
the lumbar region, the left axillary fossa, the right in-
guinal region, the ventral abdominal region and the
left lateral thorax region. In each of the regions,
TEWL, skin hydration and skin pH were measured. Be-
fore the measurement, hair was clipped to 1 mm length
using Metzenbaum scissors. In a study by Watson et al,
clipping did not influence the results of TEWL.
17
The
measurement was taken 2 min after hair clipping, a pe-
riod of time used by other investigators.
17
For each pa-
rameters six successive measurements were taken and
the mean value was calculated. The assessment of the
parameters was made by means of the Courage
Khazaka Multi Probe Adapter 5 and the appropriate
probes: the Tewameter TM 300 probe (to measure
TEWL), Corneometer CM 825 (to measure skin
hydration), Skin-pH-Meter PH 905 (to measure skin
pH). The same instrumentation was used in previous
studies in dogs.
15,16,19,21
For all parameters, the mean, standard deviation
(SD) and median were calculated. Statistical analysis
was conducted by the ManneWhitney Utest at
P-values of P¼0.05 (Statistica 6.0 software). For each
parameter, statistically significant differences were
calculated between the results obtained in different
regions. Additionally, statistically significant differ-
ences between the results for females and males
were calculated, taking into consideration the distri-
bution of parameters in the regions.
Results
For TEWL, the lowest values were observed in the
lumbar region (15.53 g/h/m
2
), while the highest
values were observed in the axillary fossa (18.22 g/
h/m
2
). TEWL was statistically significantly lower in
the lumbar region as compared to the left side of the
thorax region (P¼0.016), the axillary fossa
(P¼0.0004), the ventral region (P¼0.005), and the
inguinal region (P¼0.009) (Table 1,Fig 1).
Table 1. TEWL in different regions in cats.
Mean g/h/m
2
Median SD
Lumber region 10.53 10.70 3.05
Thorax 15.06 13.3 8.38
Axillary fossa 18.22 16.30 7.34
Ventral region 15 12.25 7.79
Inguinal region 15.34 13.60 5.73
TEWL
Lumbar
Th
o
r
a
x
Axilla
V
e
n
t
r
a
l
Inguinal
4
6
8
10
12
14
16
18
20
22
24
26
28
Average
Std. error
Std. dev.
Fig 1. TEWL in different regions in cats.
225The examination of biophysical parameters of skin
Author's personal copy
TEWL was higher in males (14.57 g/h/m
2
) than fe-
males (15.00 g/h/m
2
), but the differences were not
statistically significant (P¼0.89). No statistically sig-
nificant differences were observed between males
and females for TEWL in different body regions (lum-
bar region P¼0.97, thorax region P¼0.98, axilla
P¼0.91, ventral region P¼0.06, inguinal region
P¼0.57) (Table 2,Figs 2 and 3).
For skin hydration, the lowest values were observed
in the lumbar region (4.62 CU) and the highest values in
the inguinal region (18.29 CU). The value of this param-
eter was statistically significantly lower in the lumbar
region than in the left thoracic region (P¼0.000003),
the axillary fossa (P¼0.002), the ventral abdomen
(P¼0.03), and the inguinal region (P¼0.0003). There
were also statistically significant differences between
the results for the left thoracic region and the ventral
abdomen (P¼0.005) (Table 3,Fig 4).
No statistically significant differences were ob-
served for the results between males and females for
skin hydration in corresponding body regions
(P¼0.81) (Table 4,Figs 5 and 6). In females, the values
were higher (13.89 CU) than in males (12.28 CU).
Skin pH ranged from 6.39 (the lumbar region) to
6.64 (the inguinal region). Statistically significant dif-
ferences in skin pH were observed between the lum-
bar region and the axillary fossa (P¼0.02), and
between the lumbar region and the inguinal region
(P¼0.01) (Table 5 and Fig 7).
The mean skin pH value for males (pH 6.94) was
more basic than the mean female skin pH (pH 6.54)
(P¼0.004). A statistically significant difference be-
tween males and females was found for skin pH
from the left thoracic region (P¼0.004) but not for
the ventral abdomen (P¼0.09), the lumbar region
(P¼0.39), the axilla (P¼0.18) or the inguinal region
(P¼0.49) (Figs 8 and 9).
Discussion
TEWL, skin hydration and skin pH measurements are
considered to be useful techniques to assess the dam-
age of skin in humans and are widely used to evaluate
skin barrier function in patients with atopic dermatitis
as well as to evaluate the therapeutic efficacy of
locally administered treatments.
1e5,8,9
The integrity of skin barrier function is important in
the aetiopathogenesis of atopic dermatitis. In dogs
with atopic dermatitis, there are numerous defects in
Table 2. TEWL in male and female cats.
Mean g/h/m
2
Median Variance
Males 14.57650 12.80000 49.50281
Females 15.00100 12.70000 50.60481
Table 3. Skin hydration in different regions in cats.
Mean
(corneometer
units)
Median SD
Lumber region 4.62421 3.87000 4.35559
Thorax 14.18632 9.62000 15.02929
Axillary fossa 15.44421 13.08000 9.57414
Ventral region 13.38263 13.10000 7.51884
Inguinal region 18.29350 14.11500 10.75044
TEWL
-
M
a
l
e
Average
Std. error
Std. dev.
Lumbar
Thorax
Axilla
Ventral
Inguinal
4
6
8
10
12
14
16
18
20
22
24
26
28
30
Fig 2. TEWL in different regions in male cats.
TEWL
-
F
ema
l
e
Lumbar
Th
o
r
a
x
Axilla
V
e
ntr
a
l
Inguinal
6
8
10
12
14
16
18
20
22
24
26
28
Average
Std. error
Std. dev.
Fig 3. TEWL in different regions in female cats.
226 MP Szczepanik et al
Author's personal copy
skin barrier function. Marsella et al found ultrastruc-
tural changes in the epidermis in such animals.
24
Atopic dogs have abnormalities in lipid lamellae orga-
nisation and wider intracellular species containing ab-
normal lipid material.
24
Lamellar lipids are reduced in
number and highly disorganised.
29
Lipid lamella are
also markedly heterogenous compared to normal
dogs.
30
It is hypothesised that these defects are re-
sponsible for enhanced penetration of environmental
allergens and increased risk of sensitisation in predis-
posed patients.
24
Reiter et al and Pin et al also ob-
served a decrease in the amount of ceramides in the
skin in atopic dogs.
31,32
Ceramides are the largest
group of stratum corneum lipids. A ceramide defi-
ciency is associated with an increase in TEWL and
may be involved in impaired skin barrier function.
31
In veterinary medicine, information regarding these
biophysical parameters in different diseases is lim-
ited.
21,22,26
There is also little information concerning
the baseline values of these parameters in different an-
imal species with most information obtained from ca-
nine studies. With the exception of pH, TEWL and
skin hydration have not been investigated in cats.
Research conducted by other authors has pointed to
statistically significant differences in the case of TEWL
between different dog breeds. Hestler et al determined
that TEWL values differ significantly between Beagles
and Basset Hounds.
16
Differences in TEWL between
breeds have also been described by Young et al.
15
TEWL may vary in different body regions in people
27
and dogs.
11,17
Oh and Oh found that TEWL in Beagles is
the lowest for ear pinnae and for the lumbar region, as
compared to other body regions,
11
with the highest
values found on the head and the tail. Yoshihara et al,
who also took measurements with Tewameter TM
300, showed that the lowest values of TEWL are found
in the lumbar region.
18
A similar relationship was
found in the present study, in that TEWL was lowest
in the lumbar region, which was statistically
corneome
t
ry
Average
Std. error
Std. dev.
Lumbar
Thorax
Axilla
Ventral
Inguinal
-5
0
5
10
15
20
25
30
35
Fig 4. Skin hydration in different regions in cats.
Table 4. Skin hydration in male and female cats.
Mean Median SD
Males 12.28436 9.930000 9.04522
Females 13.89281 9.720000 12.05099
corneometry - ma
l
e
Average
Std. error
Std. dev.
Lumbar
Th
o
r
a
x
Axilla
V
e
n
t
r
a
l
Inguinal
0
5
10
15
20
25
30
35
Fig 5. Skin hydration in different regions in male cats.
corneometry - female
Lumbar
Th
o
r
a
x
Axilla
V
e
ntr
a
l
Inguinal
-5
0
5
10
15
20
25
30
35
40
Average
Std. error
Std. dev.
Fig 6. Skin hydration in different regions in female cats.
227The examination of biophysical parameters of skin
Author's personal copy
significantly different from values obtained for other re-
gions. In contrast, Watson et al, determined that the
lowest TEWL values were found in the ventrum in
dogs.
17
Previous studies regarding values of this pa-
rameter have not been conducted in cats, therefore, a di-
rect comparison of results in the present investigation
and other studies cannot be made.
The influence of body region on skin pH in animals
was investigated by Meyer et al
28
In this investigation,
various animal species (cattle, horses, goat, sheep), in-
cluding dogs of different breeds and cats were stud-
ied. They concluded that there were no statistically
significant differences in skin pH of different body re-
gions. This is in contrast with the results of the present
study. Similarly, research in humans has shown that
pH values vary according to site.
25
Having compared
the values of skin pH, Mayer et al concluded that skin
pH obtained from most sites in cats was slightly acidic
at 5.94e6.81, as compared to the results in the present
study of 6.39e6.64.
Young et al assessed the influence of sex on TEWL,
skin hydration, and skin pH
15
in Beagles, Fox Terriers,
Labrador Retrievers and Manchester Terriers. In this
study, the sex did not significantly influence the
parameters, although males exhibited a larger range
in skin pH than females.
15
These results correlate with
the results obtained in the present study in regards to
TEWL and the hydration of the epidermis. However,
in the present study a significant difference in skin pH
between males and females was observed (6.94 in
males, 6.54 in females). The influence of sex on skin
pH was also examined by Mayer et al and Bourdeau
et al
13,28
These authors also failed to observe any influ-
ence of sex on skin pH in cats, but in cattle, the pH
values of males were more basic than in females.
28
Table 5. Skin pH in different regions in cats.
Mean (pH) Median SD
Lumber region 6.394000 6.340000 0.281395
Thorax 6.570000 6.480000 0.354933
Axillary fossa 6.628500 6.625000 0.452842
Ventral region 6.553684 6.460000 0.443123
Inguinal region 6.643158 6.600000 0.509826
p
H
Lumbar
Thorax
Axilla
Ventral
Inguinal
6,0
6,2
6,4
6,6
6,8
7,0
7,2
Average
Std. error
Dev. error
Fig 7. Skin pH in different regions in cats.
pH
Male Female
5,6
5,8
6,0
6,2
6,4
6,6
6,8
7,0
7,2
7,4
7,6
7,8
8,0
8,2
Average
Std. error
Dev. error
Fig 8. Skin pH in male and female cats.
p
H
Average
Std error
Dev. error
M - r a b m u L
F - r a b m u L
M - x a r o h T
F - x a r o h T
M - a l l i x A
F - a l l i x A
M - l a r t n e V
F - l a r t n e V
M - l a n i u g n I
F - l a n i u g n I
5,0
5,5
6,0
6,5
7,0
7,5
8,0
8,5
9,0
9,5
Fig 9. The distribution of skin pH in different regions for
male and female cats.
228 MP Szczepanik et al
Author's personal copy
Matousek and Campbell also found that male dogs had
a more basic pH than females in dogs.
14
We anticipate that the assessment of biophysical pa-
rameters of skin, especially TEWL, will be useful in
understanding atopic dermatitis in cats. Much re-
mains to be known about atopic dermatitis in cats,
and the diagnosis of this disease can be challenging.
The diagnosis is made on the basis of historical and
clinical features and immunological tests (positive
skin tests or increase of specific IgE) and the exclusion
of other skin diseases which exhibit similar clinical
signs.
33
In dogs, it is known that there are differences
in TEWL in non-lesional skin between healthy dogs
and dogs with atopy, with an increase in TEWL in
atopic dogs. It is possible that such a relationship in
cats exists, and disturbances in biophysical para-
meters of skin may be useful tools in the early diagno-
sis of atopy in this species.
The knowledge of skin pH in cats may also be use-
ful in topical therapy. It is known that in dogs a in-
crease of pH is found in pyoderma.
26
In dogs the
use of topical products containing ethyl lactate, ben-
zoyl peroxide, chlorhexidine, calicic acid, and sulfur
causes a normalisation in skin pH, and it is possible
to shorten the duration of topical therapy by using
agents with pH similar to dogs skin.
26
In cats, similar to dogs and humans, there are dif-
ferences between body regions in biophysical param-
eters of skin. Further research is necessary in order to
specify the range of values of the biophysical para-
meters in healthy cats, and to assess them in various
cutaneous diseases.
Acknowledgements
The authors thank Wiesław Sitkowski for statistical
review.
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... Non-invasive methods used commonly in the process of assessing skin condition include the examination of a number of biophysical skin parameters such as transepidermal water loss (TEWL), skin hydration (SH), skin pH and erythema intensity as revealed in the literature (Beco and Fontaine 2000, Hester et al. 2004, Shimada et al. 2009, Szczepanik et al. 2011, Szczepanik et al. 2012, Szczepanik et al. 2013. Biophysical skin parameters (TEWL, SH, skin pH) have been assessed in dogs, cats, horses and laboratory animals (Matousek and Campbell 2002, Popiel and Nicpoń 2004, Fluhr et al. 2006, Szczepanik et al. 2016, Yoshihara et al. 2007 first of the mentioned methods, TEWL, is most commonly used and considered as the most accurate assessment of epidermal damage and Shimada et al. (2008) have shown that this is also a good parameter to evaluate skin barrier functions correlating well with the degree of lesions assessed clinically and histopathologically. ...
... Polish Journal of Veterinary Sciences Vol. 21, No. 1 (2018) TEWL may depend (Beco and Fontaine 2000, Szczepanik et al. 2011, Momota et al. 2013, Szczepanik et al. 2016) on such factors as body region, age, sex or breed and the hair coat has been considered as one of the factors that may cause variation of TEWL values. The assessment of transepidermal water loss in animals has been performed after different types of skin preparation (unclipped or clipped with different methods using scissors or an electric clipper). ...
... The assessment of TEWL in animals has recently been the subject of numerous studies (Hester et al. 2004, Lau-Gillard et al. 2010, Szczepanik et al. 2011, Szczepanik et al. 2016, where it has been examined in different body regions of several animal species. The assessment of transepidermal water loss in animals has been performed after different types of skin preparation. ...
Article
The measurement of transepidermal water loss (TEWL) is one of the biophysical skin parameters used to assess skin barrier function. Assessment of transepidermal water loss, may depend on such factors as body region, age, sex or breed and the hair coat has been considered as one of the factors that may cause variation of TEWL values. The aim of our research was an examination of the influence of clipping on the amount of TEWL. The examination was performed with 12 Wielkopolska horses with Courage Khazaka Multi Probe Adapter 5 and a TEWL TM 300 probe. The TEWL values were statistically constant in the clipped site, while the values in the unclipped sites were not. Hair clipping of examined sites is recommended for TEWL measurement in horses.
... The evaluation of cutaneous barrier integrity involves measurements of biophysical parameters such as transepidermal water loss (TEWL), skin hydration (SH), skin surface pH or erythema severity (Shimada et al. 2008, Szczepanik at al. 2011, Zając et al 2014. The first of the above-mentioned methods, namely TEWL, is commonly used and considered to be directly related to skin barrier dysfunction; this is also a commonly used method of evaluating skin barrier functions in the dog correlating well with the degree of lesions assessed clinically and histopathologically (Shimada ey al. 2008, Zając et al. 2014. ...
... For TEWL measurements, two types of evaporimeters were used: with open and closed chambers. Studies on animals have been conducted, both with open-chamber (Hightower et al. 2010, Ohmori et al. 2010, Szczepanik et al. 2011, Marsella 2012, Zając et al. 2014) and closed-chamber (Hester et al. 2004, Shimada et al. 2008, Oh and Oh 2009, Momota et al. 2013, Pellicoro et al. 2013, Pin et al. 2014. As judged by some authors, closed-chamber instruments may be more reliable because in this type of device body--induced airflow around the chamber is avoided, while in open-chamber tewameters turbulent airflow around the probe may affect the accuracy of the measurement. ...
... Biophysical skin parameters have been investigated in healthy dogs, cats and horses ( Oh and Oh 2009, Lau-Gillard et al. 2011, Szczepanik et al. 2011, 2012, Momota et al. 2013. Evaluation of TEWL has been carried out on allergic animals (dogs and cats). ...
Article
Allergic skin diseases in cats are amongst the most prevalent dermatological conditions in this species. The objectives of this study were to evaluate different types of skin barrier measurements in healthy cats and cats with non-flea non-food hypersensitivity dermatitis (NFNFHD). 24 clinically healthy and 19 NFNFHD cats were included in this clinical trial. In each animal, the transepidermal water loss (TEWL) and skin hydration (SH) were assessed on six clipped body sites by VapoMeter SWL 4605 and Corneometer ®CM 825, respectively. Results of TEWL measurement were , significantly higher in one of the six examined body sites, namely on the lumbar area (p=0.0049). Furthermore, a statistically significant difference was found between the average TEWL values (p=0.019). Statistically notable differences were measured at least in one certain body site for SH: in the groin (p=0.02), where the values in the affected cats were lower than in the healthy individuals. These results may suggest that in NFNFHD cats transepidermal water loss is higher than in healthy cats. Skin hydration is, at least, in certain body sites, lower in atopic feline patients than in healthy individuals.
... Previous research on humans and domestic animals found sex-based variation in skin pH and therefore we predicted there would be variation in skin pH between sexes in bats. However, the direction of the sex effect varied among species and studies (Jenkinson and Mabon, 1973;Ruedisueli et al., 1998;Giacomoni et al., 2009;Szczepanik et al., 2011), so we could not predict the direction of the effect in bats. Finally, while we could not make directional predictions about site-specific variation in bat skin pH, we expected that roost site characteristics might affect bat skin pH, predicting that skin pH might vary among capture locations. ...
... In many temperate insectivorous bats, the sexes largely segregate from early spring through mid-summer with females forming maternity colonies and males in bachelor groups (Kunz and Fenton, 2003). Skin pH is higher in males than females in dogs (Ruedisueli et al. 1998), cats (Szczepanik et al., 2011) and cattle (Jenkinson and Mabon, 1973;Meyer and Neurand, 1991), although other studies on various domestic mammals found no difference between the sexes (Supplementary Table S1). In humans, there are conflicting results concerning which sex is more acidic (Giacomoni et al., 2009). ...
Article
Full-text available
Skin is a key aspect of the immune system in the defence against pathogens. Skin pH regulates the activity of enzymes produced both by hosts and by microbes on host skin, thus implicating pH in disease susceptibility. Skin pH varies interand intra-specifically and is influenced by a variety of intrinsic and extrinsic variables. Increased skin alkalinity is associated with a predisposition to cutaneous infections in humans and dogs, and inter-specific and inter-individual variation in skin pH is implicated in differential susceptibility to some skin diseases. The cutaneous pH of bats has not been characterized but is postulated to play a role in susceptibility to white-nose syndrome (WNS), a fungal infection that has decimated several Nearctic bat species. We used non-invasive probes to measure the pH of bat flight membranes in five species with differing susceptibility to WNS. Skin pH ranged from 4.67 to 8.59 and varied among bat species, geographic locations, body parts, age classes, sexes and seasons. Wild Eptesicus fuscus were consistently more acidic than wild Myotis lucifugus, Myotis leibii and Perimyotis subflavus. Juvenile bats had more acidic skin than adults during maternity season but did not differ during swarming.Male M. lucifuguswere more acidic than females during maternity season, yet this trend reversed during swarming. Bat skinwas more acidic in summer compared to winter, a pattern also reported in humans. Skin pHwas more acidic in captive than wild E. fuscus, suggesting environmental impacts on skin pH. The pH of roosting substrates affects skin pH in captive bats and may partially explain seasonal patterns in wild bats that use different roost types across seasons. Future research on the influence of pH on microbial pathogenic factors and skin barrier function may provide valuable insights on new therapeutic targets for treating bat skin conditions.
... Biophysical skin assessment, although widely applied in human medicine and cosmetology, is still rarely used in veterinary medicine. So far, the use of the following properties has been studied in animals: transepidermal water loss (TEWL), skin hydration (SH), pH level and intensity of skin erythema, yet the majority of assessments have been made in dogs and cats [1][2][3][4][5]. Assessments of skin properties in horses have only recently become the subject of scientific interest for researchers-they have studied TEWL, SH, pH and the probable influence of animal breed and hair removal on the results obtained. ...
... This does not explain, however, why these values were increased only in the group of stallions. Studies carried out by Szczepanik et al. [4,17] showed some lower TEWL values in the lumbar region than in other locations in horses. Additionally, some differences were observed both between breeds and body regions-in particular in the lumbar and inguinal regions [6]. ...
Article
Full-text available
This study aimed to assess the biophysical parameters of the skin in Polish Konik horses (Polish primitive horses). According to the authors, this is the first assessment performed on such a wide scale in this group of animals. The evaluation carried out is innovative both with regards to the breed of the animals and the wide scope of the physicochemical skin assessment. The study group comprised mares, stallions and geldings, and the evaluations concerned transepidermal water loss, corneometry, pH, skin temperature assessment and mexametry. These parameters were assessed in five skin regions: the lips, the right ear, the prosternum, the right side of the neck and the chest. The measurements were taken after spreading the hair apart, with the use of a Multiprobe Adapter System (MPA ® ) and dedicated probes (Courage + Khazaka electronic GmbH, Cologne, Germany). The measurements revealed statistically significant differences in the values of transepidermal water loss in the lips in mares compared with stallions (P = 0.023) and also in stallions compared with geldings (P = 0.009). Corneometry showed significantly higher results in the neck region in mares compared with stallions (P = 0.037) and the prosternum areas in mares and geldings compared with stallions (P = 0.037 and P = 0.018). Skin pH measurement on the right side of the neck rendered significantly higher values in stallions than in mares (P = 0.037). In geldings, the skin temperature was significantly higher than in stallions (P = 0.049). Once the appropriate physicochemical values for specific animal species and breeds are determined, non-invasive methods of skin examination in many diseases and also methods of evaluation of the efficacy and/or adverse effects of applied medications can be established.
... Other studies have evaluated whether there is a correlation between the intensification of the severity of clinical symptoms, measured by CADESI 03 and TEWL, and shown that such correlation is present for some of the assessed body areas (6,10). Particular parameters, especially TEWL, but also epidermis hydration or skin pH, have previously been studied in healthy dogs, cats, and horses (7,13,16,(18)(19)(20). Moreover, it has been found that TEWL increases when the epidermis is damaged and is thus a reliable parameter for evaluating skin barrier function in dogs (17). ...
Article
Full-text available
The aim of this study was to demonstrate whether there is a correlation between transepidermal water loss (TEWL) and the severity of skin lesions in cats with feline atopic dermatitis (AD). The severity of symptoms was determined by using 2 scoring systems for clinically assessing the skin lesions in cats: Scoring Feline Allergic Dermatitis (SCORFAD) and Feline Extent and Severity Index (FeDESI). Such a correlation between TEWL and systems for clinically evaluating symptoms has already been shown in humans and dogs. Measurements were taken in 18 European Shorthair cats: 11 females and 7 males. Scores were calculated using SCORFAD and FeDESI and TEWL was measured in 7 areas of the body. Correlations were calculated between SCORFAD and TEWL and between FeDESI and TEWL for each body region and the average TEWL was also calculated with each system. Positive correlations were found between SCORFAD and TEWL in 3 of the examined areas: thorax (r = 0.44, P = 0.02); axilla (r = 0.39, P = 0.04); and forelimb (r = 0.55, P = 0.02). A correlation was also found between the average TEWL and SCORFAD (r = 0.41, P = 0.03). In the case of FeDESI, a correlation was found in the forelimb (r = 0.53, P = 0.02), but no correlation was found between FeDESI and the average TEWL. The results obtained showed that TEWL can be used as an additional tool in clinically assessing atopic dermatitis in cats, although it seems to be less useful in cats than in humans. © 2018, Canadian Veterinary Medical Association. All rights reserved.
... 31,32 Cat skin pH was 6.4-6.9 with higher values in males compared with females. 33 In horse ponies, basic skin pH was 7-8 depending on the body region. 34 The skin pH values for guinea pigs were 5.5, rat 6.5, rabbit 6.7 and monkey 6.4. ...
Article
The pH plays an important physiological role in nature and humans. pH varies from 1 to 8 in human organs with tight regulation in blood and epithelia of barrier organs. The physiological pH of the stratum corneum is 4.1–5.8 and several mechanisms contribute to its formation: filaggrin degradation, fatty acid content, sodium‐hydrogen exchanger (NHE1) activation and melanosome release. First, the acidic pH of the stratum corneum was considered to present an antimicrobial barrier preventing colonization (e.g. by Staphylococcus aureus and Malassezia). Later on, it was found that the pH influences skin barrier function, lipid synthesis and aggregation, epidermal differentiation and desquamation. Enzymes of ceramide metabolism (e.g. β‐glucocerebrosidase or acid sphingomyelinase) as well as proteases (e.g. chymotryptic enzyme or cathepsin D linked to epidermal differentiation and desquamation) are regulated by the pH. Experimental disruption of the physical barrier leads to an increase of pH, returning to normal levels only after many hours. Inflammatory skin diseases and diseases with an involvement of the epidermis exhibit a disturbed skin barrier and an increased pH. This is known for atopic dermatitis, irritant contact dermatitis, ichthyosis, rosacea and acne, but also for aged and dry skin. Normalizing the pH by acidification through topical treatment helps to establish a physiological microbiota, to repair skin barrier, to induce epidermal differentiation and to reduce inflammation.
... 5 Evaluation of the integrity of the cutaneous barrier can be achieved by measuring of biophysical parameters such as trans epidermal water loss (TEWL), skin hydration (SH), skin pH or severity of erythema. Trans epidermal water loss has been reported for healthy dogs, cats and horses, and for dogs and cats with AD. [6][7][8][9][10][11][12] A correlation between the severity of clinical signs using the CADESI method and TEWL has been reported for the dog. 12 Skin hydration appears to correlate with the severity of clinical signs of some affected body sites of atopic dogs, namely the groin and interdigital regions. ...
Article
Full-text available
Background: Evaluation of the severity of clinical signs of cats with allergic skin diseases has used two scoring systems: Scoring Feline Allergic Dermatitis (SCORFAD) and the Feline Extent and Severity Index (FeDESI). The integrity of the cutaneous barrier can also be evaluated by measuring skin hydration. A correlation between the clinical score and skin hydration has been observed in humans and dogs with atopic dermatitis (AD). Hypothesis: To demonstrate a correlation between the clinical score and skin hydration of cats affected with presumed AD. Animals: European short hair cats (n = 18): 11 females and seven males with a confirmed diagnosis of AD. Methods: SCORFAD and FeDESI scores were calculated and the measurements of skin hydration were assessed from seven body sites using corneometry. The correlation between the SCORFAD and FeDESI systems and skin hydration of each site, and the average skin hydration was calculated. Results: There was a positive correlation between the SCORFAD score and skin hydration for the axilla, thorax and forelimb; for FeDESI and axilla and lumbar sites. There was a negative correlation between the FeDESI and skin hydration for the pinna (r = -0.47). Conclusions and clinical importance: Measurements of skin hydration could be a useful tool for the evaluation of allergic cats. There is limited evidence of any useful correlation between clinical scoring systems and measurements of hydration. The pinna may be a suitable region for the assessment of skin barrier function in normal and allergic cats.
Article
Background: Feline atopic syndrome (FAS) is a common disease. Single intradermal injections of heat-killed actinomycetales have shown beneficial effects in canine allergies. Hypothesis/objective: To evaluate the clinical effects of heat-killed actinomycetales [Gordonia bronchialis (GB) and Rodococcus coprophilus (RC)], alone or in combination, in FAS. Methods and materials: Privately owned cats with a diagnosis of FAS were assigned randomly in three treatment groups (GB, RC and GB/RC combination) or placebo. Five intradermal injections were performed over a one year period. At each visit [Day (D)0, D20, D40, D60, D90, D180 and D365], clinical signs, global owner assessment score, use of rescue medications, clinical adverse effects, skin hydration and cutaneous pH were assessed. Results: Seventeen cats were enrolled. When compared to the placebo group and improvement in treatment GB was sustained from D90. When compared with D0 significant improvement in the GB group was seen from D60. Over one year, a complete remission of the clinical signs was seen in 30-67% of cats in the treatment groups. A reduction in the pruritus score was seen for RC after 365 days of treatment (P = 0.04). Differences in the other variables were not seen. Conclusions and clinical importance: The use of multiple intradermal injections of heat-killed GB shows promise as effective and well-tolerated treatment for FAS. Because of the low cost and the lack of adverse effects, GB could be a beneficial treatment option for FAS. A larger study is needed to confirm these data and to evaluate the immunological changes occurring in the treated cats.
Chapter
Although very well defined and characterized in the dog, feline atopic syndrome remains less well understood with regard to disease pathogenesis and clinical presentations. While many similarities exist, questions remain whether atopic dermatitis is the same disease entity in dogs and cats. Atopic dermatitis in the cat is often referred to as “feline atopic syndrome” or “non-flea, non-food hypersensitivity dermatitis (NFNFHD).” Although the diagnostic process is similar for dogs and cats, with both being a diagnosis of exclusion, demonstration of immunoglobulin-E (IgE) involvement in feline atopic syndrome has been inconclusive. As with canine atopic dermatitis, pruritus remains a feature of the disease in cats; however, the distribution of pattern of pruritus and lesions is more variable in feline patients. Cats with feline atopic syndrome will typically present with at least one of four common cutaneous reaction patterns (head/neck/pinnal pruritus with excoriations, self-induced alopecia, miliary dermatitis, eosinophilic skin lesions). Additionally, non-cutaneous clinical signs may also be observed.
Article
The pH of the skin is tightly regulated by endogenous buffering systems. We examined the influence of buffers of different pH and composition on skin barrier repair, pH, inflammation, and epidermal thickness/proliferation/differentiation. After tape-stripping in hairless mice buffers with pH 4-7 were applied in patch test chambers. After removal of the chambers, skin pH and transepidermal water loss (TEWL) were monitored for 24 h, and biopsies were taken for histology/immunohistology. Hairless mice showed a basal skin pH of about 5.8. Following barrier disruption and application of water, the pH increased by 0.6 units; increase in pH was reduced by the pH 4 glycolate buffer, unchanged by pH 4 citrate and pH 5.5 buffers, and even increased by the pH 7 buffer. pH 5.5, pH 4 citrate, and pH 4 glycolate buffers led to a slight, while the pH 7 buffer led to a significant increase in TEWL after barrier disruption compared to water. The pH 7 buffers led to a significant increase in epidermal thickness/proliferation/differentiation and inflammation after barrier disruption, whereas buffers with pH 4 and 5.5 caused a slight increase. In conclusion, only the pH 4 glycolate buffer significantly reduced the skin barrier disruption-related increase in skin pH. This was accompanied by only slight increase in epidermal thickness and inflammation compared to water. Application of the pH 7 buffer led to a significant increase in the skin pH, TEWL, epidermal thickness, and inflammation. The results are important for the formulation of topical products for effective acidification in pathological skin conditions.
Article
Skin physiology in cats has received little attention. The aim of this study was to evaluate the long-term influence of sex, time and the level of dietary fat and energy on the dynamics and qualities of the hair coat. Twenty-four European short-haired laboratory cats were followed over a 1-year period. They were divided into eight groups of three, according to: sex (12 males and 12 females), sexual status (intact or neutered) and diets [(high energy 4300 kcal/kg as fed, 21% fat) vs. (moderate energy 3500 kcal/kg as fed, 10% fat)]. Both diets were fed for 6 months to all cats following a cross-over design. The following parameters were evaluated throughout the study: thickness of hair coat and hair lengths (neck, rump, lateral, flank), hair regrowth (after periodic clippings of 25 cm2 areas), and telogen/anagen ratio. The thickness of the hair coat initially varied from 1.2–1.7 cm on the neck, 1–1.4 cm on the rump, 1.8–2.5 cm on the flank, and hair shaft lengths were 1.7–2.5, 3.7–3.9 and 2.5–3.2 cm, respectively. Comparison of values revealed few statistical differences: increase of the thickness of hair coat in neutered cats (male and female) during the study, and increase of the length of lateral hairs in all groups during the study. Over all periods and in all groups, the curve of growth was similar (rapid then slower). Some transient variations were attributed to temporary changes in ambient conditions. In conclusion, neither sex, nutrition or season (in housed cats) influenced the general quality of hair coat, in particular hair regrowth.Funding: Royal Canin.
Article
Many studies have focused on the relationship between barrier damage and human atopic dermatitis. Currently, evaluating human skin barrier function depends on measuring transepidermal water loss (TEWL) by Evaporimeter. However, applying this method clinically to dogs is impractical due to the influences of air turbulence and vapour from the hair coat. To minimize these influences, we developed and evaluated a new method for measuring TEWL using a closed chamber system. Dry air was injected into a closed chamber placed on the dog's skin surface, and the vapour content of recovered air was detected with a quartz crystal sensor as a frequency variance. At first, a frequency decrease attributable to hair coat vapour was observed, and then the frequency gradually increased and became constant. The steady state value was used to calculate TEWL. It was unnecessary to restrict a dog's movement to control independent environmental effects. Transepidermal water loss was measured in 18 beagles with normal skin at seven different anatomical sites. Results confirmed it was possible to measure TEWL without clipping hair at the inguinal site. Funding: Kao Corporation.
Article
Skin lipids and pH are two factors classically considered of importance in homeostatic characteristics of skin. Skin physiology in cats has received little attention. The aim of this study was to evaluate the long-term influence of sex, sexual status, season, and dietary fat and energy on these parameters. Twenty-four European short-haired laboratory cats, 14 months of age, were followed over a 1-year period. They were divided into 8 groups of three, according to: sex (12 males and 12 females), sexual status (intact or neutered) and diets [(high energy 4300 kcal/kg as fed, 21% fat) vs. (moderate energy 3500 kcal/kg as fed, 10% fat)]. Both diets were fed to all cats for 6 months following a cross-over design. Parameters regularly evaluated were skin pH and hair total lipid content (extraction from samples of 0.6–1.2 g of clipped hairs). The pH of the skin varied from 6.6–6.8 initially to 7.2–7.4 at the end of the study. This increase was significant only in intact animals (male and female). The dietary changes did not affect skin pH. Hair total lipid content was not affected by sex or the diets but slightly increased in all groups over the study period from 1.5–2.4 to 2.4–3.3%. In conclusion, skin pH appeared to be potentially modified by sexual status, but not by sex or dietary lipids and energy. Hair lipids do not appear to be affected by sex or increases in dietary lipids and energy. The slight increase in pH and hair lipids during the study was attributed to the change from young adult to adult stage of all cats. Funding: Royal Canin.
Article
In this double-blind, within-patient vehicle-controlled study, patients with mild-to-moderate atopic dermatitis (AD) were treated for 3 weeks twice daily with pimecrolimus cream 1% on one forearm and with vehicle cream on the other forearm. Efficacy of treatment was assessed clinically using the Atopic Dermatitis Severity Index (ADSI), the Investigators Global Assessment (IGA) and the pruritus visual analogue scale. In parallel, blood microcirculation in the skin was measured as an objective parameter for skin inflammation. Skin hydration and transepidermal water loss (TEWL) were monitored as parameter relevant for the barrier function. Treatment with pimecrolimus cream 1% resulted in a quick and marked improvement of signs and symptoms of AD and a significant reduction of microcirculation from 33.90 to 15.55 AU (P < 0.0001). Skin hydration increased continually from 42.86 to 52.69 AU (P = 0.002) and TEWL decreased from 35.30 to 21.50 g/m(2)/h (P = 0.001), indicating restoration of skin barrier. At vehicle-treated sites changes of skin physiological parameters were less pronounced and observed only initially with later plateau or even reversal. At the end of the study, there were significant differences for all measured skin physiological parameters between pimecrolimus cream 1% and vehicle: microcirculation 12.15 AU (P = 0.004), skin hydration 7.12 AU (P = 0.002), TEWL 11.38 g/m(2)/h (P = 0.004). Non-invasive evaluation of microcirculation and barrier functionality thus represent a valuable tool for the objective assessment of treatment response to pimecrolimus cream 1%.
Article
Transepidermal water loss (TEWL) was measured as assessment of barrier function in house dust mite-sensitized atopic (n = 24) and normal (n = 21) beagle dogs before and after allergen challenge. Dogs of the two groups were matched for age and housed in the same environment. Ten sites were evaluated including both areas of high and low predisposition to atopic lesion formation. On day 0 (before allergen exposure) and day 3 (3 days after allergen exposure), TEWL measurements were taken using an open-chamber evaporimeter. On day 0, significant differences (one-way ANOVA) were found between normal and atopic dogs in the chin, pinna, periocular region, axilla, antebrachium and thorax. Within the atopic group, a significant increase (one-way ANOVA) in TEWL was found in the axilla on day 3. Such a difference was particularly marked in young dogs (chin, pinna, axilla, antebrachium and groin). Within the normal group, allergen challenge did not change TEWL except for the chin. When atopic and nonatopic sites were compared within the atopic group, a significant difference in TEWL was found on day 0. A two-way ANOVA showed a significant effect of site, a significant effect of time but no site x time (i.e. allergen exposure) interaction. It is concluded that the house dust mite-sensitized atopic beagle dogs used in this study have altered barrier function in 'atopic' areas and that such differences are more evident in young individuals and are aggravated by allergen exposure.
Article
This study evaluated changes in transepidermal water loss (TEWL), skin hydration and intercorneal lipid content in dogs with atopic dermatitis (AD). TEWL and skin hydration were measured in the inguinal skin of 10 dogs with AD and 30 normal dogs. TEWL was significantly higher in both lesional skin (94.3 +/- 38.8 g/m(2)/h) and non-lesional skin (28.8 +/- 9.5) of dogs with AD than healthy controls (12.3 +/- 2.3) (P < 0.05). Water content in the lesional skin of dogs with AD (15.8 +/- 7.0 AU) was significantly lower than that of controls (24.2 +/- 8.8) (P < 0.05), whereas no significant differences were recognized in water content between non-lesional skin of dogs with AD and controls. To compare the lipid content between lesional and non-lesional skin of dogs with AD and controls, intercorneal lipids, extracted from the stratum corneum, were quantified by thin-layer chromatography. The relative amounts of ceramides in the lesional skin (24.4 +/- 5.6%) and non-lesional skin (25.6 +/- 3.8%) of dogs with AD were significantly lower than those in controls (31.4 +/- 6.9%) (P < 0.05). Conversely, no significant differences were recognized in the relative amounts of cholesterols and free fatty acids (FFA) between dogs with AD and controls. Moreover, there are statistical correlations between TEWL and the relative amounts of ceramides, but not those of cholesterols and FFA, in both lesional and non-lesional skin of dogs with AD. These results strongly suggest that decreased ceramide content accelerates TEWL in dogs with AD, similar to the situation seen in the corresponding human disease.
Article
Impairment of skin barrier function has been hypothesized in canine atopic dermatitis (AD). In this prospective, controlled study, the ultrastructure of the upper epidermal layers was investigated using an experimental model of canine AD. Seven atopic Beagles sensitized to Dermatophagoides farinae and four healthy Beagles were used as controls. Both normal and atopic dogs were challenged with D. farinae for 3 days. Clinical signs were scored and skin biopsies were taken from the inguinal area before and 3 days after allergen exposure. Samples were processed to enhance lipid visibility and evaluated by Transmission Electron Microscopy. Emphasis was placed on evaluation of the lipid lamellae (LL), and lamellar bodies (LB) of the stratum corneum.After allergen challenge, atopic Beagles developed severe pruritic dermatitis while no skin lesions were noted in the controls. Ultrastructurally, before allergen challenge, atopic Beagles displayed focally severe abnormalities in LL organization and wider intercellular spaces containing abnormal lipid material. In atopic Beagles, LBs were frequently found inside corneocytes while this finding was not observed in the controls. After allergen challenge, further increase of intercellular spaces was observed in the stratum corneum of atopic Beagles while no appreciable changes were observed in the normal dogs. Intercellular spaces in atopic Beagles were filled with abundant amounts of abnormal lipid material and highly disorganized LL. It is concluded that baseline differences in the ultrastructure of the skin exist between normal and experimentally sensitized atopic Beagles and that these changes are aggravated by allergen challenge and the resulting flare-up of dermatitis.
Article
To establish a standardised clipping method for the measurement of transepidermal water loss (TEWL) with a VapoMeter in Beagle dogs and to identify the optimal anatomical site for TEWL measurement. TEWL values obtained from skin sites on five healthy Beagles clipped using two different blade angles (standard vs non-standard) were compared. TEWL values for 48 h were also obtained from seven different anatomical sites that had differing hair density. The hair was clipped in the intensively haired anatomical sites (head, lower and upper back and tail), but not clipped in the sparsely haired sites (ear, inguinal region, footpad). The TEWL values for the standard and non-standard clipping sites were 6.3 +/- 1.31 and 27.2 +/- 1.11 g/h/m(2), respectively. We found the upper back among the clipped sites was the most appropriate site for TEWL measurement over 48 h after clipping, whereas among the unclipped sites the ear was the most appropriate, because the TEWL values from those anatomical sites had the least fluctuation and were less affected by movement. The clipping method and anatomical site should be standardised in order to minimise the experimental variation in TEWL measurement in dogs.