Melanocytes of the hair bulb are responsible for hair colour. They transfer their melanosomes to the surrounding hair keratinocytes. In the hair folli- cles, melanin granules are mainly in the cortex, their long axes parallel to the hair surface.
Involvement of hair in vitiligo macules is variable, indicating that the follicular compartment of the melanocyte organ may be spared while the epidermal compartment is destroyed by the 'vitiligo' process. This dissoci- ated behaviour of epidermal and follicular melanocytes is very common in vitiligo.
The incidence of body leukotrichia in the different series of the literature varies from 10% to more than 60% (Dutta & Mandal 1969; Seghal 1974).
Poliosis occurs in both patients with bilateral or unilateral vitiligo. Its inci- dence has been estimated at 48.6% in a group of 101 patients with segmental vitiligo (Hann & Lee 1996). A few or all body hair of a single m a d e may be amelanotic and not all macules are uniformly involved. Presence of leukotrichia has been accorded special significance. In these instances, transplantation of melanocytes is required for repigmentation.
The occurrence of leukotrichia is not correlated to disease activity. A recent study demonstrates that the disease does not progress more signifi- cantly in patients with leukotrichia than in patients with normal hair pig- mentation (Hann et al. 1997).
77
CHAPTER 10
DePiPentationof HairandMucous Membranes
Vitiligo of the scalp usually presents as a localized patch of white or grey hair, but total depigmentation of all scalp hair may happen (Fig.lO.3). On the contrary, only a few follicles may be involved leading to a scattering of white hairs on the scalp (Fig. 10.4) (Lerner & Nordlund 1978). The interfollicular scalp epidermis may be involved with or without associated leukotrichia (Fig. 10.5). Isolated early greying or whitening before 30 years of age has also been suggested to represent a form of vitiligo.
Histological and ultrastructural studies suggest that in greying or whiten- ing of hair resulting from the ageing process, abnormal melanocytes are still present in the follicle, whereas in white hair of vitiligo, all melanocytes have been lost.
All hairy areas of the body may be involved, including eyebrows, eye- lashes and pubic hair (Figs 10.6 & 10.7). Spontaneous repigmentation of depigmented hair in vitiligo does not occur.
Until recently, little attention was paid to vitiligo leukotrichia. This clinical feature has been accorded special significance. It is considered as a sign that the involved area will not repigment with medical therapies because it indicates that the melanocyte reservoir within the hair follicle has been destroyed. This statement implies that spontaneous or therapy-
Fig. 10.3 Extensive vitiligo of the scalp.
Fig. 10.4 Single hair involve- ment in a patient with vitiligo.
induced repigmentation of vitiligo leukotrichia is very unlikely. Three CHAPTER 10
vitiligo patients undergoing epidermal grafting and PUVA therapy showing repigmentation of leukotrichia in the eyebrows have been reported (Hann et al. 1992). Repigmentation of vitiligo hair after der- mabrasion and split thickness skin grafting of vitiligo macules over hair-bearing areas has also been observed. These isolated reports have been confirmed by a systemic study demonstrating that surgical (dermabrasion and thin split thickness skin grafting) repigmentation of vitiligo could be achieved, partial to nearly total, in seven out of eight patients (Agrawal & Agrawal1995).
DViPentation of Hair and Mucous
Membranes
Fig. 10.5 Depigmentation of the scalp skin without changes of hair colour.
Fig. 10.6 Poliosis of the eyelids.
79
CHAPTER 10
Depigmentation of Hair and Mucous Membranes
Fig. 10.7 Vitiligo macule on the external genitalia includ- ing the glans penis. Localized depigmentation of pubic hair.
References
Agrawal, K. & Agrawal, A. (1995) Vitiligo: surgical repigmentation of leukotrichia. Der- Coondoo, A., Sen, N. & Panja, R.K. (1976) Leucoderma of the lips. Aclinical study. Indian Dummet, C.O. (1959) The oral tissues in vitiligo. Oral Surgery, Oral Medicine, and Oral Dutta, A.K. & Mandal, S.B. (1969) A clinical study of 650 vitiligo cases and their classifica- Gaffoor, P.M. (1984) Depigmentation of the male genitalia. Cutis 34,492-494.
Hann, S.K. & Lee, H.J. (1996) Segmental vitiligo: clinical findings in 208 patients. Journal of the American Academy of Dermatology 35,671-674.
Hann, S.K., Im, S., Park, Y.K. & Hur, W. (1992) Repigmentation of leukotrichia by epider- mal grafting and systemic psoralen plus UV-A (letter). Archives of Dermatology 128, 998-999.
vitiligo. International Journal of Dermatology 36,353-355.
de Gynocologie et D’obstetrique (Paris) 16,193-225.
1183-1187.
ing programme. British Journal of Venereal Diseases 57,145-146.
matologic Surgery 21,711-715.
Journal Of Dermatology 21,29-33.
Pathology 12,1073-1079.
tion. Indian Journal of Dermatology 14,103-111.
Hann, S.-K., Chun, W.H. & Park, Y.-K. (1997) Clinical characteristics of progressive Jayle, F. & Aubry, H. (1921) Le vitiligo gknital et abdominal chez la femme. Revue Francaise Lerner, A.B. & Nordlund, J.J. (1978) Vitiligo. What is it? Is it important? J A M A 239, Moss, T.R. &Stevenson, C.J. (1981) Incidence of male genital vitiligo. Report of a screen- Seghal, V.N. (1974) Aclinical evaluation of 202 cases of vitiligo. Cutis 14,439445.
11: Ocular and Otic Findings in Vitiligo
M O N T E D. MILLS A N D D A N I E L M. ALBERT
Introduction
The eye, as a pigmented organ, is susceptible to many congenital and acquired abnormalities of pigmentation which affect the skin and other pigmented tissues. The eye contains two populations of pigmented cells:
1 the pigment epithelial layers of the retina, ciliary body and iris, and 2 the melanocytes of the uvea.
The latter resemble the melanocytes of the skin. In patients with vitiligo both types of pigmented cells of the eye, as well as the melanocytes in periocular cutaneous tissues, may be affected, presumably by the same pathophysio- logical mechanism affecting the skin. Various forms of intraocular depig- mentation have been observed in patients with cutaneous vitiligo. Most importantly, inflammatory ocular abnormalities including the Vogt- Koyanagi-Harada syndrome (VKH) and nonspecific idiopathic uveitis have been associated with cutaneous vitiligo. Other autoimmune diseases thought to be associated with vitiligo, including Graves' disease and dia- betes mellitus, may also affect the eyes. Pigmented cells are also found in the inner ear, and sensorineural hearing loss may be seen in patients with VKH as well as those with non-VKH vitiligo. The purposes of this chapter are to review the ocular and otic abnormalities which have been reported in associ- ation with vitiligo, and discuss the possible pathophysiological mechanisms for eye and ear involvement in this pigmentary disorder.