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Hypopigmentation

June 27, 2008

By Watkins, Jean

VITILIGO This man had patchy loss of pigment on his hands and around his mouth. The white macules, of otherwise normal looking skin, were increasing in size and were itching. Vitiligo is said to be an acquired inflammatory disorder in which melanocytes in the skin fail to function. It is a common problem affecting about 1 per cent of the population, 30 per cent of those affected have a family history of the condition, and of these 30 percent may have problems with other autoimmune conditions, such as thyroid disease.

DIAGNOSIS OF VITlLIGO-WOOD’S LIGHT

The diagnosis of vitiligo can usually be made on clinical grounds. Lesions are often bilateral. The skin is essentially normal apart from the depigmentation and there is no scaling, thickening or inflammation. If viewed under Wood’s light, the contrast between the pigmented and depigmented skin is emphasised. If there is any doubt, skin scrapings may be taken to exclude fungal infection or a biopsy performed. Checks on thyroid function, blood glucose and B12 levels should be made to exclude problems in these areas.

RE-PIGMENTATION AND MANAGEMENT OF VITILIGO

Islets of pigmentation around the follicles may indicate the start of a spontaneous recovery. Active treatment is more effective if given early. GPs should initiate topical steroids before seeking specialist advice. Only potent or very potent preparations seem to be effective, and may be used once a day, except on thin-skinned areas, for up to eight weeks. Topical immunosuppressants such as tacrolimus are recommended. Narrow band UVA, may induce long remissions and appears to be more effective than PUVA.

PITYRIASIS VERSICOLOR

This woman had ‘pale patches’ on her neck and upper chest for some time. The irregularly shaped macules showed areas of scaling. When viewed under a Wood’s lamp a yellow-green fluorescence was noted. The condition was thought to be pityriasis versicolor, which is caused by the yeast Malassezia. A skin scraping, mixed with potassium hydroxide, showed hyphae and yeasts. The condition responded well to the application of a topical azole preparation. Alternatives are selenium sulphide orterbinafine gel, and if this fails to respond, oral ketaconazole or itraconazole may be required.

POST-INFLAMMATORY HYPOPIGMENTATION

The skin shows an inflammatory response to a variety of trauma. Substances are released that alter the activity of immune cells and the melanocytes that affect the colour of the skin. In some cases this may lead to increased pigmentation, in others hypopigmentation follows. In the case of this woman she had been scratching her back for months. Although the skin may take a long time to re-pigment, it tends not to be a permanent change. If it is in a situation that causes problems for the patient, cosmetic camouflage may improve the appearance.

GENITAL LICHEN SCLEROSIS

This woman presented with itching of the vulva. She had controlled it with topical clobetasol cream applied daily. She was advised to increase the cream to twice daily. A biopsy was taken to exclude malignant change. Lichen sclerosis (LS) presents with shiny, white, smooth-topped papules. Patients with genital LS should be followed up, because malignant change can occur. Treatment involves potent topical steroids. Alternatives are calcipotriol cream, retinoids or systemic steroids. Surgery may be necessary if the vaginal opening is narrowed or in men where there are problems with micturition.

EXTRA-GENITAL LICHEN SCLEROSIS’

In about 15-20 per cent of cases, LS may occur at sites other than the genital area. The lesions are ivory white, atrophie patches. They may occur anywhere on the body but are most common on the front of the wrists, neck, upper part of the chest or around the umbilicus. They may remain symptomless and treatment is not normally necessary. The cause of LS is thought to be an immune process in which there are antibodies to one of the components of the skin. It may occur at any age but when it presents in children, it usually resolves with puberty.

PLAQUE MORPHEA-LOCALISED SCLERODERMA

This woman had noticed skin changes in the upper abdomen. The indurated skin looked pale. A biopsy of the lesion confirmed the diagnosis of morphea. This is the most common type of presentation of morphea, with thickened patches of variable size. Initially they appear mauve but later become white, shiny and hairless, with a lilac edge. It may persist for several years before softening leaving an area that may be depressed and brown. The cause of this condition may follow local injury, viral infections or pregnancy. There is no effective treatment for the problem.

Reference: Douglas W, Whitton M. What’s new in vitiligo? Dermatology in Practice 2008; 16:1

Contributed by Dr Jean Watkins, a sessional GP in Hampshire

Copyright Haymarket Business Publications Ltd. May 16, 2008

(c) 2008 GP. Provided by ProQuest Information and Learning. All rights Reserved.




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