Vitiligo

Vitiligo may be thought of as an uncommon condition, but in fact around 1% of the population has it. Vitiligo is characterised by areas of skin that lose their pigment (Figure 13.7). For reasons that are not entirely clear, melanocytes, which are the pigment making cells, are destroyed. It is not certain what triggers this, although it may be related to an injury such as sunburn or to psychological stress. There are three possible theories as to why the melanocytes behave in this way.

1. Abnormally functioning nerve cells injure the melanocytes;
2. There is an autoimmune response in which the body’s own immune system attacks the melanocytes as they are viewed as foreign bodies;
3. The melanocytes destroy themselves.

Whatever the mechanism may be, areas of totally depigmented skin are created, often symmetrical in nature, in which there are few other symptoms (e.g. no scaling or inflammation). Occasionally vitiligo will be segmental in nature with asymmetric patches occurring on just one part of the body.

When the disease is seen in children, there is a much greater likelihood of spontaneous repigmentation than in adults. Repigmentation starts around the hair follicle and then spreads across the patch until the spots coalesce. For adults the disease may be progressive with more and more areas of skin becoming depigmented, for others the patches are more static. Many will notice cycles in which there are periods of fairly rapid pigment loss, followed by periods of stability, followed by further loss of pigment, etc. Vitiligo is clearly more obvious in skin types 4 and above. But for all skin types it can have a serious impact on the individual’s psychological well-being. Individuals also have to take a great deal of care when out in the sun, as the areas of depigmentation are much more prone to burning than the rest of the skin. Pigment loss is not limited to the skin; for some people there is also pigment loss from the hair leading to white or grey head hair, eyebrows, eyelashes or body hair.