Vitiligo Causes

What causes vitiligo?

Healthy skin contains melanin, a brown pigment produced from the amino acid tyrosine by pigment cells (melanocytes) in the skin. Melanin is the pigment that determines the colour of skin, hair, and eyes. It is produced in cells called melanocytes. If melanocytes cannot form melanin or if their number decreases, skin colour will become progressively lighter. If skin affected by vitiligo is examined under the microscope, the melanocytes are absent and there are signs of inflammation in the deeper layer of the skin. It is not known exactly why some people develop this condition and others do not. Some experts believe it is an autoimmune disorder (in which an individual's immune system reacts against part of their own body). In vitiligo, specific autoantibodies against a patient's melanocytes are found in the blood, although it is not known whether autoantibodies are the cause or an effect of the damage seen. There are many autoimmune disorders and some families are more prone to this group of conditions as a whole. Another explanation for vitiligo suggests it is due to a nerve disorder, because nerve damage has been associated with pigment loss in the area of skin served by the nerve.

The severity of vitiligo differs with each individual. Light skinned people usually notice the pigment loss during the summer as the contrast between the affected skin and sun tanned skin becomes more distinct. People with dark skin may observe the onset of vitiligo any time. In a severe case pigment may be lost from the entire body. The eyes do not change colour. There is no way to predict how much pigment an individual will lose. The degree of pigment loss can vary within each vitiligo patch which means that there may be different shades of brown in a vitiligo patch. This is called ‘trichrome’. A border of darker skin may circle an area of light skin. Vitiligo frequently begins with a rapid loss of pigment which may be followed by a lengthy period when the skin colour does not change. Later, the pigment loss may begin again. The loss of colour may continue until, for unknown reasons, the process stops. Cycles of pigment loss followed by periods of stability may continue indefinitely.

Vitiligo is equally common in men and women. It can appear at any age but 50 per cent of patients are under 20 when it first appears. Symptoms involve the physical appearance as well as its psychological impact.