Family doctor

WHAT IS VITILIGO?

Vitiligo is a harmless but at times very unsightly condition where white patches develop due to loss of brown melanin pigmentation in specific areas of the skin. The name vitiligo comes from the Greek vitelius meaning calf as patches resemble white spots on a calf.

Vitiligo is common affecting about 1% of the population. Although not a serious condition the appearances of vitiligo can be devastating particularly in darker skinned people. The patches can be confined to a limited area of the body, be widespread or even cause total pigment loss.

WHAT CAUSES IT

There is total loss of melanocytes, the pigment-producing cells of the body in the affected areas. These cells have been destroyed by the immune system. Vitiligo is one of a group of disorders known as tissue-specific autoimmune diseases. Other conditions in this group include alopecia areata causing hair loss, thyroiditis, pernicious anaemia where there is attack on stomach cells and Addisons Disease with attack on the adrenal glands. In each the immune system specifically attacks these tissues. Blood tests can help screen for other autoimmune conditions although the majority of vitiligo-sufferers will not get any of these conditions.

The immune system is controlled by immune regulatory genes. Certain genes can predispose the immune system to react against itself in certain circumstances. There is a family history of the condition in about 30% of vitiligo sufferers.

TREATMENT

Vitiligo remains a difficult condition to treat, especially old established patches. Although the melanocytes in the affected skin are destroyed, small numbers survive in hair follicles. Recovery of pigment will begin in these sites. Areas with little hair such as hands and feet often will not respond as well to treatment.

General Measures

Sun protection is helpful as the white areas will burn easily. Keeping the surrounding skin from tanning will make the vitiligo less noticeable as there is less colour contrast.

Artificial tanning creams can also help and will not aggravate the process. There are very good proprietary concealing preparations such as Dermablend.

Topical steroids

Strong topical steroids such as Dermovate or Dermol can decrease the immune system attack on the pigment cells and allow the melanocytes to recover in some cases. They should not be used for more than a few weeks at a time as they may cause atrophy (thinning) of the skin.

Ultraviolet Light Treatment (PUVA)

PUVA stands for psoralens with Ultraviolet Light A band. Psoralens drugs that sensitise the skin to light. They can be used as a pill or as a topical solution. The skin is exposed to carefully calculated doses of UVA light. This may stimulate any remaining melanocytes to produce pigment. The skin must be carefully protected from sun during treatment or severe burns can result. This treatment is only available through a dermatologist.

Depigmentation of remaining skin

In some the pigment loss in an area is so extensive that only a small areas of pigmented skin are left. Bleaching preparations can be used to remove these with an improvement of the appearance.

FUTURE DIRECTIONS

Healthy melanocytes may be harvested from unaffected areas and grown in culture dishes, then reimplanted into the affected areas. This is an experimental approach, very expensive and is not available in New Zealand.

Immune modulating drugs are a new and exciting line of research. These agents are much less harmful than steroids and may be effective in switching off the immune attack. They have not been yet properly tested in vitiligo however.