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641Indian Journal of Dermatology, Venereology, and Leprology | September-October 2013 | Vol 79 | Issue 5
Premature graying of hair
Premature graying of hair
Deepika Pandhi, Deepshikha Khanna
Deepika Pandhi, Deepshikha Khanna
1
Symposium-
Hair Disorders
ABSTRACT
Premature graying is an important cause of low self-esteem, often interfering with socio-cultural
adjustment. The onset and progression of graying or canities correlate very closely with
chronological aging, and occur in varying degrees in all individuals eventually, regardless
of gender or race. Premature canities may occur alone as an autosomal dominant condition
or in association with various autoimmune or premature aging syndromes. It needs to be
differentiated from various genetic hypomelanotic hair disorders. Reduction in melanogenically
active melanocytes in the hair bulb of gray anagen hair follicles with resultant pigment loss is
central to the pathogenesis of graying. Defective melanosomal transfers to cortical keratinocytes
and melanin incontinence due to melanocyte degeneration are also believed to contribute to
this. The white color of canities is an optical effect; the refl ection of incident light masks the
intrinsic pale yellow color of hair keratin. Full range of color from normal to white can be seen
both along individual hair and from hair to hair, and admixture of pigmented and white hair is
believed to give the appearance of gray. Graying of hair is usually progressive and permanent,
but there are occasional reports of spontaneous repigmentation of gray hair. Studies evaluating
the association of canities with osteopenia and cardiovascular disease have revealed mixed
results. Despite the extensive molecular research being carried out to understand the
pathogenesis of canities, there is paucity of effective evidence-based treatment options.
Reports of repigmentation of previously white hair following certain infl ammatory processes
and use of drugs have suggested the possibility of cytokine-induced recruitment of outer sheath
melanocytes to the hair bulb and rekindled the hope for fi nding an effective drug for treatment
of premature canities. In the end, camoufl age techniques using hair colorants are outlined.
Key words: Coronary artery disease, gray hair, hair dye, osteopenia, premature
Department of Dermatology
and STD, University College
of Medical Sciences and
Associated Guru Teg Bahadur
Hospital, University of Delhi,
1Department of Dermatology,
Chacha Nehru Bal
Chikitsalaya, Delhi, India
Address for correspondence:
Address for correspondence:
Dr. Deepika Pandhi,
Department of Dermatology
and STD, University College
of Medical Sciences and
Associated Guru Teg
Bahadur Hospital, University
of Delhi, Delhi, India.
E-mail:
deepikapandhi@rediffmail.com
INTRODUCTION
INTRODUCTION
Skin and hair contribute immensely in human
communication. Hair length, color, and style play an
important role in people’s physical appearance and
self-perception. Human beings are unique amongst
primates in having very thick, long, and highly
pigmented scalp hair. This is likely to have provided
one or more survival benefits to the humans during
the process of evolution. Firstly, selective and avid
binding of toxins and metals to melanin pigment aids
in preventing the buildup of toxic metals from fish
species which concentrate heavy metals, especially in
human development along sea coasts and riverbanks.[1]
Secondly, reactive quinone intermediates generated
during melanin synthesis possess potent antibacterial
properties. Lastly, deep brown-black hair present in 90%
of the world’s population protects against sunstroke,
and its melanin aids very efficient and fast exchange
of ion transport and efflux for adequate salt balance.[1]
However, the remaining 5-10% of world population
mostly hailing from northern Europe do not have the
environment-friendly brown-black hair, possibly due
to mutations in the melanocortin-1 receptor (MC1R),
a G-protein coupled receptor. Mutations in the MC1R
gene are believed to have contributed to white blonde,
yellow blonde, and auburn color of hair in individuals
in the less sunny climates in northern Europe, while
How to cite this article: Pandhi D, Khanna D. Premature graying of hair. Indian J Dermatol Venereol Leprol 2013;79:641-53.
Received: June 2012. Accepted: September, 2012. Source of Support: Nil. Confl ict of Interest: None declared.
Access this article online
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Indian Journal of Dermatology, Venereology, and Leprology | September-October 2013 | Vol 79 | Issue 5642
natural selection pressures possibly restrained this
mutation in the sunny tropical areas.[2,3]
Considering the important role played by hair in social
communication, premature hair graying or canities
has significant adverse effects on the appearance,
self-esteem, and socio-cultural acceptance of the
affected individual. It is often viewed as a sign of old
age and loss of health and vigor. Affected individuals
are often subjected to social stigma, discrimination,
and difficulties in marriage.
DEFINITION
DEFINITION
Canities, or hair graying, is a process of chronological
aging and occurs regardless of gender or race. The
age of graying varies with race and ethnicity. Hair
is said to gray prematurely only if graying occurs
before the age of 20 years in Whites, before 25 years
in Asians [Figures 1 and 2], and before 30 years in
Africans.[4]
NORMAL HAIR FOLLICULAR MELANIN UNIT AND
NORMAL HAIR FOLLICULAR MELANIN UNIT AND
MELANOGENESIS
MELANOGENESIS
The color of human hair depends on melanogenesis,
the process of synthesis of melanin and its subsequent
distribution from the melanocyte to keratinocyte. The
process is thought to be regulated genetically at various
levels. The human hair follicles contain two types
of melanins: the black-brown pigment eumelanins
mainly present in black and brown hair and the yellow
or red pheomelanins in auburn and blonde hair.[4]
Both epidermal and follicular melanocytes are derived
from immature melanoblasts that migrate from the
neural crest into the skin during embryogenesis.
As the hair follicle develops, the progeny of
melanoblasts which proliferate in the epidermis,
known as transient-amplifying melanocytes, leave
that compartment and move into the developing
hair follicle. There, melanocytes may become or
remain DOPA-oxidase-positive cells (i.e. express
active tyrosinase) or remain DOPA-oxidase-negative
cells (i.e. either fail to express tyrosinase or express an
inactive tyrosinase) depending on the intrafollicular
compartment in which they reside [Figure 3].[5,6]
The hair follicle melanin unit consists of one
melanocyte to five keratinocytes in the hair bulb as
a whole and one to one in the basal layer of the hair
bulb matrix. By contrast, each epidermal melanocyte
is associated with 36 viable keratinocytes in the
immunocompetent epidermal-melanin unit. Hair
follicle melanogenesis is under cyclical control
and tightly coupled to the hair growth cycle,
in contrast to epidermal melanogenesis that is
continuous. Hair growth has three periods: hair
shaft production (anagen), brief apoptosis driven
regression phase when the lower two-thirds of
hair follicle are resorbed (catagen), and a relatively
quiescent period (telogen). Melanocytes in the
hair bulb retract their melanocytes and shut
down melanogenesis towards the end of anagen.
Simultaneously there is a decline in the activity of
three main melanogenic enzymes: tyrosinase, gp75,
and dopachrome tautomerase.[4] This occurs a few
days before the cessation of keratinocyte proliferation
resulting in the pigment-free proximal ends of shed
telogen hair. During catagen, hair apoptosis occurs
and a quiescent hair follicle much smaller in size is
Figure 1: A 10-year old girl with premature canities
Figure 2: Streak of gray-white hair in a 7-year-old child without
associated vitiligo
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643Indian Journal of Dermatology, Venereology, and Leprology | September-October 2013 | Vol 79 | Issue 5
left in telogen. Melanogenic activity restarts during
early anagen with the reconstruction of the follicular
melanin unit. Tyrosinase activity becomes apparent
during anagen III, pigment transfer from hair bulb
melanocytes to cortical keratinocytes is initiated
during anagen IV and active melanogenesis continues
throughout anagen V and VI, ceasing with the onset
of catagen.[4,7] Anagen usually persists for 3-5 years,
and these follicles extrude the hair fiber at a rate of
approximately 1 cm per month.[8] Melanocytes are
Figure 3: Melanocyte stem cells and their progeny during the hair cycle (APM: Arrector pilorum muscle, SG: Sebacean gland,
IRS: Inner root sheeth, P.BMc: Pigmented hair bulb melanocytes, ORS-AMC: Outer root apoptotic melanocytes, Ap-BMc: Apoptotic
hair bulb melanocytes)
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present in two compartments of the hair follicle: in
the anagen hair bulb, where they transfer pigment to
cells that will form the hair cortex, and in the outer
root sheath (ORS). ORS melanocytes are sparsely
distributed in the basal layer of the epithelium along
the length of the follicle and are non-melanized.
However, recent studies suggest that gray hair follicles
lack melanocytes in the hair bulb while retaining those
in the ORS.[7] Hair bulb melanocytes are probably
recruited from the ORS melanocyte population at
the onset of anagen. Migration and activation of
these melanocytes is possibly under unknown local
signalling mechanisms like - melanocyte stimulating
hormone (-MSH); modulation or failure of which
may result in graying.[7] The hair bulb matrix is the
principal site for the fully differentiated follicular
melanocyte subpopulation; these melanocytes are
distributed, in particular, within the matrix above
and around the upper dermal papilla. They transfer
their melanin granules to keratinocytes of the hair
cortex and less so to the medulla and very rarely to
the hair cuticle.[9] Under stimulation from radiation
or cytokines, the ORS melanocytes may be stimulated
to migrate and differentiate to naturally repigment
graying hair follicles.[4]
AGE-RELATED CHANGES IN THE HAIR FOLLICLE
AGE-RELATED CHANGES IN THE HAIR FOLLICLE
MELANIN UNIT
MELANIN UNIT
Different types of hair fibers produced during life
include: fine unpigmented lanugo hair in the fetus or
neonate, short (mostly unpigmented) vellus hair or fine
pigmented intermediate hair and long thick terminal
hair shafts in the adult. The surface morphology of hair
also appears to change with age, most particularly with
the reduction in the cuticular scale size. Hair color on
the scalp tends to darken with advancing age.[10] The
hair bulb melanocytes have high synthetic capacity
that is greatest during youth when the scalp follicular
melanin unit is only a few cycles old. An average
scalp hair follicle usually receives 715 melanocyte
replacements from an ORS reservoir to the hair bulb in
45 years preceding onset of gray hair.[4] Senile canities
are believed to occur because of exhaustion of the
regenerative capacity of hair pigmentation as well as
through programmed events during aging.
Premature graying or canities may reflect a genetically
regulated early exhaustion of the melanocyte reservoir’s
seeding potential or some defect in cell activation/
migration compounded by environmental factors,
inflammation, or psychological stress. Nishimura
et al. suggested that loss of melanocyte stem cells
can be observed and temporarily precedes the loss of
differentiated melanocytes in the hair matrix. This
incomplete maintenance of melanocyte stem cells
appears to cause physiologic hair graying through loss of
differentiated progeny with aging.[11] The progression of
graying is compounded by the fact that with advancing
age more hair follicles remain for longer duration in the
resting phase (telogen).[4]
HISTOPATHOLOGY OF CANITIES
HISTOPATHOLOGY OF CANITIES
A line across the widest part of the bulb of the hair
follicle divides it into two regions: a lower region of
undifferentiated cells and an upper region in which the
cells become differentiated to form the inner sheath and
the hair [Figure 4]. Below this critical level known as the
line of Auber lie the matrix or the germination center of
the follicle, where every cell is mitotically active, and
the dermal papilla. From the matrix, cells move to the
upper part of the bulb, where they increase in volume
and become elongated vertically. Some of the cells in the
upper bulb still show some mitotic activity, but these are
too few to account for much of the growth of the hair.
The pigmentary unit is a pear-shaped black structure
at the tip of the dermal papilla above the Auber’s
line in pigmented hair where individual melanocytes
Figure 4: Pigmentary unit in relation to the dermal papillae and
the line of Auber
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645Indian Journal of Dermatology, Venereology, and Leprology | September-October 2013 | Vol 79 | Issue 5
cannot be distinguished.[12] Only unpigmented and
undifferentiated putative melanocyte stem cells, but
not pigmented differentiated melanocytes, are normally
found in the hair bulb below the line of Auber. In gray
hair, the pigmentary unit becomes fuzzy, melanocytes
are few and rounded, and lightly pigmented
oligodendritic melanocytes become detectable in the
proximal hair bulb below Auber’s line.[13] The resultant
pigment loss in graying hair follicles due to a marked
reduction in melanogenically active melanocytes in
the hair bulb of gray anagen hair follicles is central to
the pathogenesis of graying.[6] Defective melanosomal
transfer to the cortical keratinocytes or melanin
incontinence due to melanocyte degeneration is also
believed to contribute to graying. Ultrastructurally,
remaining melanocytes contain fewer and smaller
melanosomes. In addition, there is autophagolysosomal
degradation of melanosomes within the melanocytes
itself and is usually followed by the degeneration
of the melanocyte. Degenerative changes within the
hair follicle melanocytes are associated with the
parallel increase in dendritic cells in the anagen hair
follicle.[4] Eventually, no melanogenic melanocytes
remain in the hair bulb. True gray hair show reduced
DOPA reaction (indicator of tyrosinase activity) while
white hair bulbs are negative for the same.[4]
PATHOGENESIS OF CANITIES
PATHOGENESIS OF CANITIES
As of now, the etiology of graying is incompletely
understood. Currently, it is mainly considered to
be genetic with interplay of various environmental
factors. Premature canities may appear alone without
any underlying pathology as an autosomal dominant
condition occurring before 20 years of age. It may
also occur in association with certain organ-specific
autoimmune disorders like pernicious anemia, hyper- or
hypothyroidism, and as part of various premature aging
syndromes (e.g. progeria and pangeria) [Table 1] and
atopic diathesis.[14,15] Fifty-five percent of patients with
pernicious anemia were found to develop graying of hair
before 50 years, as compared to only 30% in the control
group.[16] Reversible hypopigmentation of hair has also
been noted in association with nutritional deficiencies
like chronic protein loss (due to kwashiorkor, nephrosis,
celiac disease, and other causes of malabsorption),
severe iron deficiency and copper deficiency.[14] Serum
copper was significantly lower in 66 patients with
premature canities, as compared to normal controls (66)
in one study. However, no difference was found in the
zinc levels, while iron concentration was higher in the
control group.[17] Binding of copper ions to the enzyme
tyrosinase, which is essential for enzyme activity and
thus the process of melanogenesis, may possibly be
affected in patients with premature canities and low
serum copper levels.[17]
Other causes implicated include stress, and
administration of certain drugs including
chloroquine, mephenesin, phenylthiourea, triparanol,
fluorobutyrophenone, dixyrazine, the epidermal
growth factor receptor inhibitor imatinib and interferon
- alpha, and use of certain chemicals (medicated
oils) and topically applied agents like dithranol,
Table 1: Syndromes manifesting with premature graying of hair[14,18,22-24]
Name Inheritance Pattern/associated complaints/presentation
Book’s syndrome AD Premolar hypodontia/bicuspid hypoplasia, palmoplantar hyperhidrosis
Progeria AD By 2 years of age, only sparse gray or white hair seen with plucked
bird facies, joint stiffness, abnormal dentition, loss of subcutaneous fat
Pangeria (Werner’s syndrome) AR Temporal graying starts in adolescence or as early as 8 years of age,
further spreads across the entire scalp accompanied by progressive
baldness by 25 years of age with sclerodermoid skin changes,
beak-shaped nose, short stature
Dystrophia myotonica AD Graying of hair followed by myotonia and muscle wasting, cataracts
Rothmund–Thompson
syndrome
AR Rapidly progressive premature canities in adolescence with
poikiloderma, photosensitivity, alopecia, cataract, short stature
Cri-du-chat syndrome Most cases due to sporadic
de novo deletion of 5p arm
Premature canities seen in one-third of patients with microcephaly,
hypotonia, and characteristic facies
Ataxia telangiectasia AR Cerebellar ataxia, immunodefi ciency, ocular telangiectasia
Fisch’s syndrome NK Early extensive premature canities with impaired hearing and partial
heterochromia iridis
Seckle syndrome (bird-headed
dwarfi sm
AR Bird-headed profi le, trident hands, skeletal defects, hypodontia,
pancytopenia
Down’s syndrome Sporadic Premature canities seen in 14% patients
AD: Autosomal dominant, AR: Autosomal recessive, NK: Not known
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chrysarobin, resorcin, prostaglandin F2 alpha (PGF2
alpha) analogs.[14,18,19] Premature graying has also been
reported in patients with HIV infection, cystic fibrosis,
and Hodgkin’s lymphoma.[18,20,21]
The extraordinary melanogenic activity of pigmented
bulbar melanocytes in the growing (anagen) hair
follicle, continuing for up to 10 years in some hair
follicles generates large amounts of reactive oxygen
species (ROS) via the hydroxylation of tyrosine and the
oxidation of DOPA to melanin and places melanocytes
under a higher oxidative stress load. Impairment
of antioxidant system with age probably leads to
accumulation of ROS and oxidative stress that damages
the melanocyte.[25] Wood et al. demonstrated catalase and
methionine reductase A and B expression and functional
loss of methionine sulfoxide repair mechanism in the
gray hair follicle.[26] Oxidative stress generated outside
hair follicle melanocytes, for example, by pollution, UV
light, psycho-emotional or inflammatory stress, may
add to this endogenous oxidative stress and overwhelm
the hair follicle melanocyte antioxidant capacity
resulting in enhanced terminal damage in the aging
hair follicle.[4,13,27-32] Superoxide radicals generated by
interaction of UV-A light with topically applied psoralen
have recently been shown to induce graying of hair in
mice. This photosensitization induced graying was,
however, averted by pre-treatment with superoxide
dismutase gel on the opposite side.[28] Bcl-2 is an
antioxidative stress protein required for maintenance
of hair follicle melanocytes at the tip of hair bulb and
lack of this protein is associated with disappearance of
melanocyte stem cell precursors.[11,13]
Alternatively, some authors have suggested that the
primary cause of hair graying may be associated with
hair growth patterns, hair growth rate, or anagen
prolongation in the hair cycle, and active hair growth
makes conditions less favorable for melanocyte
survival in the hair follicle.[33-35]
Apart from oxidative stress, other factors may also
contribute to the process of graying. Insufficient
neuroendocrine stimulation of hair follicle
melanogenesis by locally synthesized agents, such
as adrenocorticotrophic hormone, -MSH, and
-endorphin, have also been hypothesized as a
possible mechanism for hair graying.[36,37] It has been
suggested that binding sites for the pro-eumelanogenic
peptide -MSH are only expressed on melanogenically
active melanocytes in pigmented hair follicles and
their absence in senile white hair melanocytes may
render these cells unresponsive to the melanogenic
influence of this melanotrophin.[38] Cervical and
lumbar sympathectomy of long duration has also been
shown to retard the normal graying of scalp and pubic
hair, respectively, in two patients, suggesting that
sympathetic denervation somehow slows or prevents
the normal graying of hair with increasing age.[39,40]
Smoking was reported to be significantly correlated
with hair graying, and impairment of stem cell
regenerative capacity with substance abuse was
postulated to lead to graying in a single case report.[41,42]
Interestingly, absence of graying of hair over the
pinna in the presence of physiologic canities over the
scalp, beard, and moustache regions was reported in
250 Indian men over the age of 50 years. The authors
suggested the possibility of a Y-linked ethnic trait that
may have a control on the retention of pigment.[43]
Extensive research in the field of premature graying of
hair is underway at the molecular level. Bmpr2, a known
receptor for bone morphogenetic proteins (Bmps),
and Acvr2a, a known receptor for Bmps and activins,
are individually redundant but together essential for
multiple follicular traits. Reduced Bmpr2/Acvr2a
function in melanocytes in mutant mice was recently
shown to result in gray hair due to aberrant hair
shaft and melanosomes’ differentiation.[44] Stem cell
factor (SCF) and its receptor (KIT) were shown to have
an important role in signaling in the maintenance
of human hair follicle melanogenesis during the
anagen cycle and in physiological aging of the hair
follicle pigmentary unit.[45] Both Notch 1 and Notch 2
signaling pathways are required for the maintenance
of melanoblasts and melanocyte stem cells and are
essential for proper hair pigmentation in mice.[46]
EPIDEMIOLOGY
EPIDEMIOLOGY
As the age of onset of canities is dependent more on
the genotype of the individual, it is subject to racial
variation. Average age of onset in Caucasians is
349.6 years, and in Negroes, it is 43.910.3 years.[14]
Graying of hair appears between 30 and 34 years in
Japanese men and between 35 and 39 years in Japanese
women.[14] On an average, Caucasians begin to gray in
their mid-30s, Asians in their late 30s, and Africans,
latest in their mid-40s.[4] In Bantus, graying of hair is
said to be uncommon before 40-50 years of age.[47]
However, onset as early as the second decade or as late
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647Indian Journal of Dermatology, Venereology, and Leprology | September-October 2013 | Vol 79 | Issue 5
as the ninth decade is also possible.[38] A recent study
reported that 6-23% of people have 50% gray hair by
50 years of age.[48] Graying is more readily apparent and
noticed earlier in those with dark hair, but fair-haired
individuals appear totally gray earlier.[22] Both sexes
are equally affected.[38]
CLINICAL FEATURES
CLINICAL FEATURES
The hair follicle pigmentary unit is maximally
functioning during post-adolescence and early
adulthood, when terminal hair growth is optimal and
hair color has settled to its preferred tonal variant. The
onset and progression of graying correlate very closely
with chronological aging and at least a few gray hair
are found in all individuals regardless of gender or race
by 60 years of age.[49] In contrast to aging of our skin,
premature graying may not be hastened by cumulative
photodamage.[9]
In men, graying usually begins at the temples and in
the sideburns. Later it spreads to the vertex and the
remainder of the scalp, affecting the occiput last.
Women usually start graying around the perimeter of
the hairline. The rate at which an individual turns gray
depends on genetics. It is not uncommon to observe
kinships with marked early graying. The rate of graying
is also highly variable, not only on different areas of
the scalp but also across the body. This may reflect
variations in original melanocyte precursor seedings
during melanoblast migrations in embryogenesis or
in differences of niche quality.[9] Beard and body hair
are affected later. Chest, pubic, and axillary hair may
remain pigmented even in old age.[22] Jo et al. reported
temporal and occipital areas to be more commonly
involved in men than in women, with graying usually
starting in the temporal area in men but in the frontal
area in women. Initially involved scalp regions were
also different depending on age of onset; that is,
parietal or occipital area was more involved at onset
in early-onset group, whereas frontal area was more
involved initially in late-onset group. Early onset did
not mean faster progress. Rather, the extent of grayness
sharply increased after the fifth decade regardless of
age at onset.[41] Graying of hair is usually progressive
and permanent, but there are occasional reports of
spontaneous repigmentation of gray hair, and partial,
spontaneous reversal of canities may occur during the
early stages of canities, whereby melanogenesis in
de-activated bulbar melanocytes is re-started during
anagen of the same hair growth cycle.[4]
Some authors believe that the gray color is derived
from an admixture of fully white and fully pigmented
hair. Canities may affect individual hair follicles
during a single anagen VI growth phase, such that
there is a gradual loss of pigment along the same hair
shaft.[9] Full range of color from normal to white can
be seen both along individual hair and from hair to
hair. Finlay et al. reported that the perception of hair
color is affected by the physical characteristics of the
hair shaft and may bear little relationship to the true
chromacities of the shaft.[50] It has been suggested that
increased reflection of light may occur on cell interfaces
and islets of interfibrillary matrix.[14] The white color
of canities is an optical effect, that is, the reflection/
refraction of incident light masks the intrinsic pale
yellow color of hair keratin.[4] True gray hair are not
common till old age and need to be differentiated
from white hair.[51] White hair have no melanocytes
or pigmentation, while gray hair has some persisting
color with aberrantly distributed melanosomes. White
hair usually affects only the scalp and about 5% of
individuals will have whitening of hair by the fourth
decade of life.[49]
CHARACTERISTICS OF GRAY HAIR
CHARACTERISTICS OF GRAY HAIR
Gray hair is believed to be coarser, stiffer, and less
manageable than pigmented hair.[35,52] Gao et al.
reported that gray hair undergoes more severe
UV damage and needs more UV protection than
dark brown hair.[53] Gray hair often fails to hold a
temporary or permanent set, and is more resistant to
incorporating artificial color possibly due to changes in
the underlying substructure of the hair fiber. Melanin
transfer possibly decreases keratinocyte turnover
and increases keratinocyte terminal differentiation.
Aging hair follicles may thus reprogram their matrix
keratinocytes to increase production of medullary
rather than cortical keratinocytes resulting in an
enlarged and collapsed medulla, forming a central
cavity in gray and white hair.[33] This may provide
enhanced insulation to compensate for the loss of
sunlight-absorbing and heat-trapping properties of
pigmented dark hair.[4] White hair was also found to
have increased sensitivity to weathering, increased
cysteic acid residues and decreased cystine, and
increased fiber reactivity to reducing and oxidizing
agents.[52] Thickness, growth rate, and hair shaft
elongation in non-melanized hair are significantly
greater than in melanized hair.[13,33-35] White beard
hair has been shown to grow up to four times and
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have thicker hair shafts than pigmented beard hair.[34]
Besides, lack of melanin chromophore in gray and
white facial hair makes removal by laser a difficult and
complicated task.[54]
CANITIES AS A RISK FACTOR FOR SYSTEMIC DISEASE
CANITIES AS A RISK FACTOR FOR SYSTEMIC DISEASE
Premature hair graying is considered analogous
to aging and thought to reflect the aging process
happening inside. Few studies showed premature
hair graying occurring before the age of 40 years to
be an important predictor of low bone density and
osteopenia.[55,56] The association could be part of its
association with other autoimmune disorders such as
vitiligo, Addison’s disease, Grave’s disease, premature
hypogonadism, and Werner’s syndrome. Alternatively,
premature hair graying has been shown to be less
frequent in racial groups with higher bone density,
suggesting a possible genetic linkage between these
conditions.[55] Possibility of a common undefined
causative factor accelerating both the conditions
needs further exploration. Contrary to this, Morton
et al. found no association between premature graying
of hair and low bone mineral density.[57]
Various authors have reported premature graying of
hair to be a significant risk factor for coronary artery
disease (CAD).[58-60] Dwivedi et al. reported that young
CAD patients who are heavy smokers also developed
premature graying and balding. They suggested that
presence of premature hair graying in chronic smokers
indicates higher than normal risk for CAD.[60] Further,
hair graying has recently been shown to be a marker
of CAD independent of age and other traditional risk
factors in a cohort of 213 men undergoing coronary
angiography.[61] In the Copenhagen City Heart Study,
Schnohr et al. reported that risk of myocardial infarction
was directly proportional to the extent of graying of
hair in men.[58] However, in women, the association
was weaker and statistically insignificant.[58] Further,
no association was evident with life longevity in the
same study population.[62] Glasser et al. also found no
association between premature graying of hair and
increased cardiovascular morbidity, age, or cause of
death.[63]
DIFFERENTIAL DIAGNOSIS
DIFFERENTIAL DIAGNOSIS
Canities needs to be differentiated from
hypomelanotic hair disorders. The latter may
present in a diffuse or localized fashion. Pigmentary
dilution disorders include various types of
oculocutaneous albinism including Hermansky–
Pudlak and Chiedak–Higashi syndromes and Tietz
syndrome. Disorders with disrupted melanosomal
transfer resulting in characteristic silver hair include
Griscelli, Elejalde, andChediak–Higashi syndromes.
CROSS syndrome may also present with silvery
hair. In Menke’s syndrome, hair are sparse and light
colored with a steel wool quality and associated
with shaft abnormalities. Metabolic syndromes like
phenylketonuria, histidinemia, and homocystinuria
may also present with light-colored hair. Oasthouse
disease, a disorder of methionine metabolism, also
presents with light hair and recurrent edema.[14]
Localized whitening of hair, known as poliosis, may
be seen in vitiligo, piebaldism, Wardenburg syndrome,
Woolf syndrome, Ziprkowski Margolis syndrome,
and tuberous sclerosis. An acquired localized area
of white hair should prompt the clinician to look
for depigmentation of underlying skin to rule out
vitiligo [Figure 5]. Reports of sudden overnight
graying of hair (canities subita) have been attributed
to vitiligo, telogen effluvium, and alopecia areata.[64]
An acute episode of alopecia areata may present with
very sudden overnight graying due to preferential
targeting of pigmented hair by the autoimmune
pathology; this never occurs in true canities.[4]
INVESTIGATIONS
INVESTIGATIONS
Diagnosis of canities is primarily clinical. Certain
investigations such as serum vitamin B12, folic acid,
and thyroid profile may be conducted in individuals
with very early onset in the absence of any family
history.
Figure 5: Localized whitening of hair in a child with
vitiligo (leukotrichia)
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649Indian Journal of Dermatology, Venereology, and Leprology | September-October 2013 | Vol 79 | Issue 5
MANAGEMENT
MANAGEMENT
Despite the extensive molecular research being
carried out to understand the pathogenesis of canities,
treatment options still remain far from satisfactory
and no effective therapy is available. Few oral
therapies have been tried with rather inconsistent
results. Reports of successful treatment are anecdotal
and have never been confirmed by other trials. This
is surprising in view of the large number of patients
presenting with premature canities to the dermatology
outpatient department and the deep psychological and
social impact of this sign of aging. Thus, patients are
often arbitrarily prescribed nutritional supplements
containing various combinations of vitamins and
minerals like biotin, calcium pantothenate, zinc,
copper, and selenium. However, till date, the scientific
level of evidence in published literature for their
efficacy is low.
Temporary hair darkening has been reported after
ingestion of large doses of p-aminobenzoic acid (PABA)
though the mechanism of action is unknown.[18,65,66] In a
study comprising 460 gray-haired individuals, 100 mg
three times daily of PABA caused darkening of hair
in 82% patients within 2-4 months. However, relapse
was evident at 2-4 weeks after drug cessation.[18,65]
Zarafonetis reported repigmentation of hair with 12-
20 g of PABA.[66] Pasricha et al. reported successful use
of 200 mg of calcium pantothenate daily in two girls
having premature graying of hair. On a follow-up of
29 and 13 months, respectively, 300 and 1069 gray
hair were counted to have got converted into black
hair. Hair with a proximal black portion and a distal
gray part were termed as converted hair.[67] In another
study, they combined calcium pantothenate with gray
hair avulsion; at every 3-monthly follow-up, all gray
hair were avulsed from the root while any converted
hair was snipped at the gray–black junction. They
found the combination of gray hair avulsion and
calcium pantothenate to be more effective than
calcium pantothenate used alone.[68] Brandaleone
et al., however, used 200 mg of PABA with 100 mg of
calcium pantothenate (vitamin B5) and 50 g of brewer’s
yeast for 8 months to patients with gray hair without
any success.[69] Pavithran et al. reported PUVASOL
to be effective in almost two-thirds of patients with
premature graying.[70]
Repigmentation of previously gray scalp hair has
been reported following prolonged (around 3 years)
use of latanoprost, a PGF2 alpha eye drops. The
repigmentation started from the root and proximal
portion of hair and then increased over the entire
length of hair.[71] Prostaglandins are one of the
most potent stimulators of melanocyte growth and
melanogenesis.[72,73] Darkening of hair has also been
reported as an incidental finding with other drugs
such as defibrotide, cyclosporine, corticosteroid,
etretinate, L-thyroxine, verapamil, tamoxifen,
levodopa, cisplatin, acitretin, tri-iodothyronine, and
lenalidomide.[71,74-77] However, in most of these cases,
drug-induced etiology of pigmentation could only be
confirmed if hair had returned to its original color after
drug withdrawal. The same could not be confirmed as
most patients were continued on treatment with the
suspected drug.
Repigmentation of previously gray hair has also been
reported after inflammatory processes affecting the
scalp, including carbuncles, erosive candidiasis of
scalp, and exudative red dermatitis on sun-exposed
areas.[78-80] Hair darkening has also been described
after X-ray irradiation and following electron beam
therapy.[51] Shaffrali et al. reported darkening of gray
hair in two patients with porphyria cutanea tarda.[7]
Reversal of canities in the patients mentioned above
is likely to result from radiation or cytokine-induced
activation of ORS melanocytes.[4]
Paucity of systemic or topical therapies in this
condition has rendered camouflage techniques using
hair colorants as the mainstay of therapy. The use of
hair color in a patient depends on various factors such
as age of onset and psychosocial impact, especially in
terms of career opportunities. Based on the extent of
graying, different options can be adopted. Plucking out
of hair alone may be a reasonable choice if less than
10% of hair are affected. Alternatively, an individual
may choose to color only the gray hair, especially in
the beginning when graying is confined to the temples
in men or the perimeter in women.
Major types of hair colors currently used are:
temporary (textile dyes), natural coloring (e.g., henna),
semi-permanent, and permanent.[65] These may also
be classified as naturally occurring or synthetic.
Natural dyes can be of two types: substantive and
adjective. Adjective dyes alone cannot penetrate
the hair sufficiently to keep from washing or fading
away and require a mordant to adhere to the fiber.
The mordant joins with the fiber and the dye to set
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Indian Journal of Dermatology, Venereology, and Leprology | September-October 2013 | Vol 79 | Issue 5650
the color permanently. The mordant enters deeply
into the fiber, and when the dye is added, the color is
formed. Substantive dyes, on the other hand, do not
need mordant to adhere to the fiber. Traditionally used
therapies to darken gray hair include: Amalaki (Emblica
officinalis), Bhringaraj (Eclipta alba), mooncake
seed tree (Sterculia platanifolia), and the lotus
tree (Zizyphus spina-christi).[81] Henna, obtained from
the leaves of the plant Lawsonia alba, is a naturally
occurring hair colorant. It gives the auburn color and is
a substantive dye for keratin in acid solutions. Henna
carries the major advantage of being hypo-allergenic
and non-toxic in its pure form. Although the color can
add red highlights to hair, occasionally on gray hair it
may come out looking orange. The chemical lawsone
can also be obtained from Juglans regia or walnut.[81]
Temporary hair colorants consist of large molecules that
do not penetrate the cuticle and remain adherent to the
hair shaft and wash out with the next shampoo. Synthetic
dyes may also be classified as: oxidative (permanent)
or non-oxidative (semi-permanent) [Table 2]. Oxidative
dyes include permanent hair dyes, semi-permanent
hair dyes, and auto-oxidative dyes. The most
frequently used hair colorant is permanent hair dye.
All permanent hair colors contain three components:
an oxidation base also known as developer or
primary intermediates (e.g. p-phenylenediamine,
p-aminophenol, and their derivatives), a
coupler (e.g. m-phenylenediamines, resorcinol,
naphthols), and the oxidant (i.e. hydrogen peroxide
with an alkali, usually ammonia). The couplers
modify the color when used with the developer
and the oxidant. The oxidant oxidizes the primary
intermediates and, in combination with ammonia,
lightens the natural hair color.[82] Increase in pH on
addition of ammonia causes swelling of the hair fiber
and opens the cuticle of the hair, allowing the color
pigments to penetrate deep into the hair shaft. When
the color containing alkalizing agent is combined
with the developer, the peroxide becomes alkaline
and diffuses through the cuticle into the hair cortex
where melanin in located. The formation of colored
molecules from their precursors occurs inside the hair
fibers as a result of oxidation by hydrogen peroxide.
Damage of the hair shaft due to oxidation reaction
is the major disadvantage associated with use of
permanent hair color.[82] Auto-oxidative hair dyeing
involves the oxidation of dye precursors by oxygen in
air without additional oxidant. Hair is not lightened
and is therefore more suited for individuals with gray
hair.[82]
Besides concealing the undesirable gray hair, hair
dyes may also protect against photodamage. Dyed
hair shows a slower rate of degradation upon
photo-irradiation, as compared to the undyed
hair.[84] Silicone resins like trimethylsiloxysilicate and
propylphenylsilsesquioxane incorporated into hair
dyes have been reported to decrease the color change
induced by UV radiation in dyed hair.[85]
Such products have been safely used with excellent
results in millions of individuals worldwide. Studies
have raised the possibility that long-term usage of
permanent hair dyes (particularly black dyes) may be
associated with an increased risk of developing certain
cancers like lymphomas and bladder cancers. Till
date, the evidence is insufficient to state with certainty
whether there is a link between using hair dye and
cancer. However, irritant and contact allergic reactions
may develop (commonly due to p-phenylenediamine)
and can result in dermatitis and sometimes hair loss.[65]
Recent advances in the management of aging hair
and scalp are anti-aging compounds. Shampoos are
largely ineffective as anti-aging agents due to water
dilution and short contact time, and antioxidants
such as vitamin C and E in these preparations protect
fatty substances in the shampoo from oxidation, and
not the hair. Topical anti-aging compounds of current
interest are green tea polyphenols, selenium, copper,
phytoestrogens, melatonin, and as yet unidentified
substances from traditional Chinese medicine (TCM)
and Ayurvedic medicine. Use of hormonal anti-aging
protocols containing recombinant human growth
hormone has resulted in improvement of hair
thickness, hair growth, and in some cases darkening
of hair.[65] Use of L-methionine to suppress methionine
oxidation and restore the methionine-sulfoxide repair
mechanism, and thus prevent graying of hair needs
further exploration.[26] A new type of compounds (SkQs)
comprising plastoquinone (an antioxidant moiety), a
penetrating cation, and a decane or pentane linker have
been synthesized that specifically target mitochondria
and act as rechargeable antioxidants. These have been
shown to inhibit development of age-related diseases
and traits such as cataract, retinopathy, glaucoma,
balding, canities, and osteoporosis in animals.[86]
Premature graying of hair is a bothersome and
disfiguring condition causing significant interference
with social adjustment and acceptance, hence
the need for identifying effective and long-lasting
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651Indian Journal of Dermatology, Venereology, and Leprology | September-October 2013 | Vol 79 | Issue 5
Table 2: Comparison of salient features of different types of coloring agents[82,83]
Temporary Semi-permanent Permanent Demi-permanent
Structure Water soluble, organic, high
molecular weight
Small molecules (e.g. para dyes such
as diamines, aminophenols, phenols)
Combination of a developer, coupler, and
oxidant (H2O2 with ammonia)
Same as permanent color except
alkalinizing agent other than
ammonia (ethanolamine, sodium carbonate)
Mechanism Large, complex, structures that
do not penetrate the cuticle
and remain adherent to the
hair shaft till the next shampoo
Smaller molecular weight of the
molecules allows easy diffusion in
and out of the cortex
Formation of colored molecules from their
precursors occurs inside the hair fi bers as a
result of oxidation by H2O2
Same as permanent
Preparation Rinses, gel, mousses, and
sprays
Lotions or mousses Two-component kit: 1st- oxidation base,
coupler, and ammonia; 2nd- H2O2
Same as permanent
Application Applied on towel-dried hair
and left
Applied on wet shampooed hair, left
on for 10-40 min, rinsed
The mixture is initially applied near to the hair
roots for 20 -40 min to color the new growth,
followed by application to the rest of the hair
Same as permanent
Outcome/
effect
Subtle Final color of each strand is affected
by its original color and porosity, so
color is more natural and less harsh
with subtle variations across the head
Intense color Final color is more natural, gentler
Duration Only till next hair wash Washes out over a period of time,
usually lasting 6-10 shampoos
over 4-6 weeks
Color withstands normal hair washing though
some fading may occur
Washes out over 20-25 shampoos
Advantages To create special effects, to
brighten natural or dyed shade,
to remove yellowish tones from
gray hair, and to cover small
amounts (15% gray hair)
Useful for patients with up to 30%
gray hair, contains no or minimal
amount of ammonia or peroxides,
safe for damaged or fragile hair
Colour is long-lasting and suitable even for
patients with extensive involvement
There is no lifting or removal of natural
color; fi nal color is more natural; root hair
growth is less visible and a change of color
if desired is achievable; less damaging to
the hair shaft
Side effects/
disadvantages
- Gray and white hair will not dye to
the same color as the rest of the
head and some white hair will not
absorb the color at all
Roots of new proximal growth need to be
touched up every 4-6 weeks; ammonia can
cause damage to the hair
-
H2O2: Hydrogen peroxide
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Indian Journal of Dermatology, Venereology, and Leprology | September-October 2013 | Vol 79 | Issue 5652
treatment options. The future of treatment options
for premature canities lies with targeting genes and
proteins involved in hair follicle melanocyte biology.
These may aid in developing natural, biotechnological,
or semi-synthetic hair repigmentation techniques
including newer methods for delivering coloring
agents directly to the hair follicle. Further research
into the pathophysiology of hair graying not only will
reveal promising targets for intervention, but may also
provide useful links to the understanding of the aging
process as a whole.
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