Occupational contact dermatitis in painters - An analysis of patch test data from the Danish Contact Dermatitis Group

Abstract

Background. Painters are among the occupational groups that most commonly experience occupational contact dermatitis, but few investigations exist concerning this occupation.
Objectives. To characterize painters with contact dermatitis and identify the most common allergens associated with the occupation.
Materials and methods. All patch test results of 219 painters and 1095 matched controls registered by the Danish Contact Dermatitis Group between 2001 and 2010 were analysed.
Results. Hand eczema (p < 0.0001) and occupational contact dermatitis (p < 0.0001) were observed significantly more often in the painters than in the group of controls. Sensitizations to the following allergens from the European baseline series were associated with the occupation and were statistically significant: methylchloroisothiazolinone/methylisothiazolinone, epoxy resin, formaldehyde, and quaternium-15. Three different isothiazolinones emerged as the most frequent sensitizers of the allergens tested in addition to the baseline series.
Conclusions. The results indicate that painters have an increased risk of developing occupational hand eczema. Isothiazolinones and epoxy resin proved to be the two most frequent sensitizers in painters.

Full text

Contact Dermatitis •Original Article COD
Contact Dermatitis
Occupational contact dermatitis in painters – an analysis of patch test
data from the Danish Contact Dermatitis Group
Anja P. Mose1, Michael D. Lundov1, Claus Zachariae2, Torkil Menn ´
e2, Niels K. Veien3, Grete
Laurberg3, Knud Kaaber4, Christian Avnstorp5, Klaus E. Andersen6, Evy Paulsen6, Charlotte
Gotthard Mørtz6, Mette Sommerlund7, Anne Danielsen8, Jens Thormann9, Ove Kristensen10,Berit
Kristensen10,BoL.Andersen
11, Susanne Vissing12 , Niels H. Nielsen13 and Jeanne D. Johansen1
1Department of Dermato-Allergology, National Allergy Research Centre, Copenhagen University Hospital Gentofte, 2900 Hellerup, Denmark, 2Department
of Dermato-Allergology, Copenhagen University Hospital Gentofte, 2900 Hellerup, Denmark, 3Dermatology Clinic, Vesterbro 99, 9000 Aalborg, Denmark,
4Dermatology Clinic, Bredgade 30, 7400 Herning, Denmark, 5Dermatology Clinic, Roskildevej 264, 2610 Rødovre, Denmark, 6Department of Dermatology
and Allergy Unit, Odense University Hospital, Odense, Denmark, 7Department of Dermatology, ˚
Arhus University Hospital, ˚
Arhus, Denmark, 8Dermatology
Clinic, Baneg ˚
ardspladsen 1, 1570 Copenhagen, Denmark, 9Dermatology Clinic, Skovgade 23C, 7100 Vejle, Denmark, 10Dermatology Clinic, Bredgade 50,
4400 Kalundborg, Denmark, 11Dermatology Clinic, Havnepladsen 3A, 5700 Svendborg, Denmark, 12 Dermatology clinic, Gl. Hovedgade 14, 2970 Hørsholm,
Denmark, and 13Dermatology Clinic, Bindeledet 15, 2880 Bagsværd, Denmark
doi:10.1111/j.1600-0536.2012.02074.x
Summary Background. Painters are among the occupational groups that most commonly
experience occupational contact dermatitis, but few investigations exist concerning this
occupation.
Objectives. To characterize painters with contact dermatitis and identify the most
common allergens associated with the occupation.
Materials and methods. All patch test results of 219 painters and 1095 matched
controls registered by the Danish Contact Dermatitis Group between 2001 and 2010
were analysed.
Results. Hand eczema (p<0.0001) and occupational contact dermatitis (p<
0.0001) were observed significantly more often in the painters than in the
group of controls. Sensitizations to the following allergens from the European
baseline series were associated with the occupation and were statistically significant:
methylchloroisothiazolinone/methylisothiazolinone, epoxy resin, formaldehyde, and
quaternium-15. Three different isothiazolinones emerged as the most frequent sensitizers
of the allergens tested in addition to the baseline series.
Conclusions. The results indicate that painters have an increased risk of developing
occupational hand eczema. Isothiazolinones and epoxy resin proved to be the two most
frequent sensitizers in painters.
Key words: allergens; contact dermatitis; epoxy resin; hand eczema;
methylchloroisothiazolinone/methylisothiazolinone; occupation; painters;
preservatives.
Correspondence: Jeanne D. Johansen, Department of Dermato-Allergology,
National Allergy Research Centre, University Hospital of Copenhagen
Gentofte, Niels Andersens Vej 65, 2900 Hellerup, Denmark.
Tel: +45 39777301; Fax: +45 39777118; E-mail: jedu@geh.regionh.dk
Conflicts of interest: The authors have declared no conflicts.
Accepted for publication 22 January 2012
Previous studies in Germany and the United Kingdom
have shown that painters belong to one of the
occupational groups in which employees have the highest
risk of developing occupational contact dermatitis (1,
2). This is because of exposure to allergens such as
preservatives and synthetic resins, rubber chemicals, if
rubber gloves are used, or irritants such as solvents,
detergents, cleansing agents, and hand cleaners.
©2012 John Wiley & Sons A/S
Contact Dermatitis 1

OCCUPATIONAL CONTACT DERMATITIS IN PAINTERS •MOSE ET AL.
In Denmark, the National Board of Industrial Injuries
registered a total of 126 cases of occupational skin diseases
among Danish painters in the period between 2005
and 2010 (National Board of Industrial Injuries, pers.
comm. 2011). Such observations merited a more detailed
investigation, as national registries are commonly
incomplete, as a result of underdiagnosis and under-
reporting of the disease (1).
The composition of paints has undergone profound
changes over time. Today, the professional use of solvent-
based paints has been almost entirely replaced by the use
of water-based paints, which contain significantly lower
concentrations of organic solvents (3). The chemistry of
modern paints is, however, much more complex than
that of their predecessors (4). The use of primarily water-
based paints increases the need for effective preservation,
which is known to carry a risk of contact allergy, both
in painters (5, 6) and in consumers (7), but also in paint
production (8, 9). The problems of occupational contact
dermatitis in painters have been addressed in relatively
few studies so far (5, 6, 10 –12). The recent introduction
of the preservative methylisothiazolinone (MI) in high
concentrations in paints may potentially increase the
problem (13). This also creates a need for an update
concerning the characteristics of painters with contact
dermatitis and the relationship with different allergens.
The aim of this study was to analyse registered patch
test data from the Danish Contact Dermatitis Group
and hence characterize painters with contact eczema
in addition to identifying the most common allergens
associated with the profession.
Materials and Methods
In the present study, patch test results of all painters
registered in the National Database for Contact Allergy
at the Department of Dermato-Allergology, Copenhagen
University Hospital Gentofte, Denmark, by the Danish
Contact Dermatitis Group between 2001 and 2010,
were selected and analysed. Today, the Danish Contact
Dermatitis Group consists of a network of privately
practising dermatologists and three hospital dermatology
departments throughout Denmark.
The patients included in this study were patch tested
with the European baseline series and, in some cases, with
additional allergens, according to each patient’s personal
history of exposure. Patch tests were applied to the upper
back and remained occluded for 48 hr. Readings were
performed on D2, D3/D4, and D7, in accordance with the
recommendations of the International Contact Dermatitis
Research Group (14). Reactions that were scored as
1+,2+or 3+were interpreted as positive reactions,
and used for further analyses. The patch test materials
utilized may have varied between patients, because
different hospital departments and privately practising
dermatologists reporting to the National Database for
Contact Allergy follow local preferences.
The painters were extracted from the database by
means of the Danish version of the International Classi-
fication of Occupation (Disco) codes (7141 and 7142).
Consequently, the definition of painters in this study is
as follows: house, automobile and naval painters, artists,
sign writers, and paperhangers. Owing to the use of Disco
codes, it was not possible to distinguish further between
the occupational subgroups. Each painter was matched
with 5 other patients, that is, controls, who were not reg-
istered as painters in the database. Matching criteria were
age, sex, and test year. The painters and their controls
were compared by means of the MOAHLFA (Male, Occu-
pational dermatitis, Atopic dermatitis, Hand eczema, Leg
dermatitis, Face dermatitis, Age above 40 years) index,
which had been routinely registered for each patient by
the treating physician. In cases where painters (n =3)
had been retested during the study period, only results
from the last patch test were included in the analyses.
Allergens from the following main groups in the Euro-
pean baseline series were chosen for comparison between
the painters and their matches: metals, preservatives,
rubber chemicals, and synthetic and natural resins.
Selection was made on the basis of previously known
sensitizers commonly found as ingredients in water-based
paints (15).
Likewise, all additional allergens that the painters had
been patch tested with were also extracted from the
database. However, because of an extensive list of results,
we chose to limit the presentation to the group of allergens
with the highest percentage of positive allergic reactions
in our group of painters.
All data analyses were performed with the statistical
software SPSS™version 18.0. The χ2-test was applied for
the analyses of the MOAHLFA index and the patch test
results of allergens selected from the European baseline
series. A 5% level of statistical significance was used
(p<0.05), with all p-values being two-sided.
Results
A total of 36 147 patients were patch tested between
2001 and 2010. Out of the total group, 219 patients
were registered as painters, with the Disco codes 7141
and 7142. The male/female ratio was 2.4 (155 males and
64 females). The youngest painter tested was 16 years of
age, and the oldest was 68 years of age; the mean age for
whole group was 39 years.
©2012 John Wiley & Sons A/S
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OCCUPATIONAL CONTACT DERMATITIS IN PAINTERS •MOSE ET AL.
Table 1. MOAHLFA index
Painters (n =219)
n(%)
Controls
(n =1095) n (%) p-value∗
Male 155 (71) 775 (71) 1.00
Occupational 78 (36) 156 (14) <0.0001
Atopic dermatitis 40 (18) 175 (16) 0.40
Hand dermatitis 126 (58) 475 (43) <0.0001
Leg dermatitis 9 (4) 44 (4.0) 0.95
Face dermatitis 34 (16) 168 (15) 0.95
Age >40 years 106 (48) 530 (48) 1.00
∗χ2-test.
The results according to the MOAHLFA index are
shown in Table 1. It shows that the most common
anatomical site of dermatitis concerning the painters was
the hands (58%). This was followed by the face (16%) and
the legs (4%). When these characteristics were compared
between the two groups, only hand dermatitis was seen
significantly more often (p<0.0001) in the painters.
Moreover, the painters had occupational dermatitis
significantly more often (p<0.0001) than their controls.
A total of 94 painters (43%) and 409 of their controls
(37%) had at least one positive patch test reaction. On
comparison, this characteristic was of no significance
(p=0.12).
Most of the positive patch test reactions in painters
with regard to the allergens preselected from the
European baseline series were to: nickel sulfate
(15%), methylchloroisothiazolinone (MCI)/methyliso-
thiazolinone (MCI/MI) (10%), epoxy resin (8%),
methyldibromo glutaronitrile (5%), and formaldehyde
(5%) (Table 2). Sensitization to MCI/MI (p<0.0001),
epoxy resin (p<0.0001), formaldehyde (p=0.003)
and quaternium-15 (p=0.004) was found significantly
more often in the painters than in their controls. In total,
6 painters were positive to quaternium-15; all of these
were also positive to formaldehyde.
The percentage of painters sensitized to allergens that
are not included in the European baseline series and
that are classified as preservatives was especially high.
These results are shown in Table 3. The most common
allergens among the preservatives were MI (2-methyl-
4-isothiazolin-3-one) (11/41, 27%), octylisothiazolinone
(octyl-4-isothiazolin-3-one) (5/21, 25%), and benzisoth-
iazolinone (1,2-benzisothiazolin-3-one) (7/37, 19%). No
cases of allergy to acrylates or isocyanates were found
among the 15 painters tested with these substances.
Discussion
In this study, the painters were diagnosed with
occupational contact dermatitis and hand eczema
significantly more often (p<0.0001) than their controls.
This is very much in line with previous studies of painters,
which have concluded that they have an increased risk of
developing contact dermatitis (1, 2, 11, 12). This is best
exemplified by a study performed in northern Bavaria,
Germany, which showed that painters belong to one of
the 12 occupations with the highest risk of occupational
contact dermatitis (16).
Similarly, a questionnaire study among 2000 male
construction workers showed that painters reported
more symptoms of hand dermatitis than carpenters (5).
Another study showed that, in a group of 202
construction painters who worked with water-based
paint, 25 (12%) painters gave a history of hand eczema
and 16 (8%) had current problems (6). These findings
show that painters may have an increased risk of
developing hand eczema.
Four allergens (MCI/MI, epoxy resin, formaldehyde,
and quaternium-15) from the European baseline series
emerged as important, as contact allergy to these was
found significantly more often in the group of painters
than in the controls. Other studies have reported
similar results. Fisher et al. reported that the most
frequent allergens related to work as a painter were
the isothiazolinones (6). In our study, 10% of the painters
tested positive to MCI/MI, as compared with only 1% of
the controls (Table 2). Our results further show that
a high percentage of painters tested positive to MI
alone (27%), but also to octylisothiazolinone (25%)
and benzisothiazoline (19%) (Table 3). These results
clearly suggest that there are significant problems with
the isothiazolinones that are currently used in paints.
Similarly, two recently published cases of airborne
allergies caused by MI, resulting in allergic contact
dermatitis and asthma, may indicate an undisclosed
problem in painters (7).
In our study, epoxy resin came second to MCI/MI as
the allergen with the highest number of sensitizations
in painters. It caused allergic reactions in 8% of the
painters (Table 2). Other studies have shown that epoxy
resin is the most common allergen among painters. On
the basis of reports of occupational skin diseases in a
register in northern Bavaria, Bock et al. found that 6 of
55 painters (11%) had an occupationally relevant allergy
to epoxy resin (12). A Finnish study showed that the
highest risk of hand dermatitis was found among painters
who used solvent-based epoxy and urethane paints on
a daily basis (5). As a final point, it is noteworthy that,
since 1981, individuals in Denmark have been required
to take a course on personal safety if working with epoxy.
Our data show that, despite such preventive measures,
problems concerning sensitization to epoxy remain.
©2012 John Wiley & Sons A/S
Contact Dermatitis 3

OCCUPATIONAL CONTACT DERMATITIS IN PAINTERS •MOSE ET AL.
Table 2. Positive patch test reactions in the painters and the controls to allergens that are included in the European baseline series and that
may be present in paints, glues, or putties
Positive patch test reactions
Concentration (%) Vehicle
Painters
(n =219) n (%)
Controls
(n =1095) n (%) p-value∗
Potassium dichromate 0.5 Pet. 7 (3) 25 (2) 0.4
Nickel sulfate 5 Pet. 32 (15) 137 (13) 0.4
Cobalt chloride 1 Pet. 8 (4) 28 (3) 0.4
Thiuram mix 1 Pet. 1 (0.5) 13 (1) 0.3
Mercapto mix 1 Pet. 1 (0.5) 7 (1) 0.8
Mercaptobenzothiazole 2 Pet. 1 (0.5) 5 (0.5) 1.0
Methylchloroisothiazolinone/methylisothiazolinone 0.01 Aqua 22 (10) 10 (1) <0.0001
Formaldehyde 1 Aqua 11 (5) 19 (2) 0.003
Quaternium-15†1 Pet. 6 (3) 7 (0.5) 0.004
Paraben mix 15 Pet. 2 (1) 6 (0.5) 0.5
Methyldibromo glutaronitrile 0.3 Pet. 10 (5) 37 (3) 0.4
Epoxy resin 1 Pet. 18 (8) 22 (2) <0.0001
Colophonium 20 Pet. 6 (3) 28 (3) 0.9
Vehicles for the test material: aqua, deionized water; Pet., white petrolatum.
∗χ2-test.
†All cases of quaternium-15 allergy were also positive to formaldehyde, which means that quaternium-15 was of no independent importance
as an allergen in painters.
Table 3. Patch test results for some of the additional allergens that
the painters were tested with
Allergens
Total
tested
Positive patch
test reactions
n(%)
Preservatives
Methylisothiazoline
(2-methyl-4-isothiazolin-3-one)
41 11 (27)
Octylisothiazolinone
(octyl-4-isothiazolin-3-one)
21 5 (25)
Benzisothiazolinone
(1,2-benzisothiazolin-3-one)
37 7 (19)
Bioban™P 1487 [mixture of
4-(2-nitrobutyl)-morpholine and
4,4-(2-ethyl-2-nitrotrimethylene)
dimorpholine]
6 1 (17)
2-Bromo-2-nitropropane-1,3-diol (bronopol) 167 9 (5.4)
Diazolidinyl urea 191 9 (4.7)
DMDM hydantoin
(1,3-dimethylol-5,5-dimethylhydantoin)
42 1 (2.4)
Iodopropynyl butylcarbamate
(3-iodo-2-propynyl-butylcarbamate)
155 3 (1.9)
Imidazolidinyl urea 191 3 (1.6)
Only the group of allergens with the highest percentage of positive
allergic reactions is presented.
No cases of contact allergy to acrylates or isocyanates
were found. These allergens were not routinely tested,
but only tested if they were found to be relevant
according to the exposure analysis. Contact allergy
to isocyanates is especially seen in the automobile
industry and in the production of paints and binders (17).
Isocyanates are strong allergens, and may sensitize
after just one exposure (18). The diagnosis of contact
allergy to isocyanates is difficult to make (19), and cases
may easily be overlooked, which may also have been
the case in the current investigation, where only 15
painters were tested with isocyanates. Contact allergy to
acrylates has been seen in, for example, printers and
paint factory workers exposed to ultraviolet lacquers
and varnishes (20). Acrylate allergy may also have been
underdiagnosed in our investigation.
The results of this study also show that formaldehyde
is a common allergen among painters, as 11 painters
(5%) had been sensitized to this chemical. Similarly,
Moura et al. found that formaldehyde had caused
sensitization in 5% of a group of painters with
occupational dermatitis (11). Consequently, even though
formaldehyde is present in only small amounts in many
water-based paints and other painters’ products (21), it
evidently still causes a significant number of sensitizations
in painters. This might be related to the concomitant
use of formaldehyde-releasers in paints (22). Recent
studies have shown that patients who are allergic to
formaldehyde often have simultaneous contact allergy
to a formaldehyde-releaser(s), and that a contact allergy
to either can be elicited by the other (23, 24). In line with
this, the formaldehyde-releaser quaternium-15 emerged
as the fourth most important allergen from the European
baseline series causing sensitization in painters. However,
this substance is not a typical preservative in paints, and,
in all cases of quaternium-15 allergy, cosensitization to
formaldehyde was seen. Thus, quaternium-15 was of no
independent importance as an allergen in painters.
©2012 John Wiley & Sons A/S
4Contact Dermatitis

OCCUPATIONAL CONTACT DERMATITIS IN PAINTERS •MOSE ET AL.
In conclusion, the results of this study indicate that
painters have an increased risk of contact hand eczema
caused by their work. The isothiazolinones and epoxy
resin emerged as the most frequent sensitizers in painters
with contact dermatitis. Further research regarding
the relationship between the painters’ chemical work
environment and contact dermatitis, as well as better
protection, is of utmost relevance.
Acknowledgements
Drs Hans Lomholt and Henrik Sølvsten (Aalborg), Anne
Hjorther and Bent Staberg (Rødovre), Aksel Otkjær and
Morten Østerballe (Herning), Henrik Thormann (Vejle)
and Mads Nielsen and Rune Lindskov (Copenhagen) are
gratefully acknowledged for participating in the data
collection.
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Contact Dermatitis 5