Vitiligo
Vitiligo: Excerpt from Professional Guide to Diseases (Eighth Edition)
Marked by stark-white skin patches that may cause a serious cosmetic problem, vitiligo results from the destruction and loss of pigment cells. It shows no racial preference, but the distinctive patches are most noticeable in blacks. Repigmentation therapy, which is widely used in treating vitiligo, may necessitate several summers of exposure to sunlight; the effects of this treatment may not be permanent.
Causes and incidence
Although the cause of vitiligo is unknown, inheritance seems to be a definite etiologic factor because about 30% of patients with vitiligo have family members with the same condition. Other theories implicate enzymatic self-destructing mechanisms, autoimmune mechanisms, and abnormal neurogenic stimuli.
Some link exists between vitiligo and many other disorders that it often accompanies — thyroid dysfunction, pernicious anemia, Addison’s disease, aseptic meningitis, diabetes mellitus, photophobia, hearing defects, alopecia areata, uveitis, chronic mucocutaneous candidiasis, and halo nevi.
The most frequently reported precipitating factor is a stressful physical or psychological event — severe sunburn, surgery, pregnancy, loss of a job, bereavement, or some other source of distress. Chemical agents, such as phenols and catechols, may also cause this condition.
Vitiligo affects about 1% of the population in the United States, usually people between ages 10 and 30, with peak incidence around age 20. It affects men and women equally, but women are more likely to seek treatment.
Signs and symptoms
Vitiligo produces depigmented or stark-white patches on the skin; on fair-skinned whites, these are almost imperceptible. Lesions are usually bilaterally symmetrical with sharp borders, which occasionally are hyperpigmented. Lesions that are small initially can enlarge and even progress to total depigmentation (universal vitiligo).
These unique patches generally appear over bony prominences on the back of the hands; on the face, the axillae, genitalia, nipples, or umbilicus; around orifices (such as the eyes, mouth, and anus); within body folds; and at sites of trauma. The hair within these lesions may also turn white. Because hair follicles and certain parts of the eyes also contain pigment cells, vitiligo may be associated with premature gray hair and ocular pigmentary changes. (See Recognizing vitiligo.)
Diagnosis
Diagnosis requires an accurate history of onset and of associated illnesses, a family history, and observation of characteristic lesions. Other skin disorders such as tinea versicolor must be ruled out.
Confirming diagnosis In fair-skinned patients, Wood’s light examination in a darkened room detects vitiliginous patches; depigmented skin reflects the light, and pigmented skin absorbs it. Biopsy will show normal skin except for the absence of melanocytes. If autoimmune or endocrine disturbances are suspected, laboratory studies (such as thyroid studies) are appropriate.
Treatment
Repigmentation therapy combines systemic or topical psoralen compounds (trimethylpsoralen or 8-methoxypsoralen) with exposure to sunlight or artificial ultraviolet light, wavelength A (UVA). New pigment rises from hair follicles and appears on the skin as small freckles, which gradually enlarge and coalesce. Body parts containing few hair follicles (such as the fingertips) may resist this therapy.
Because psoralens and UVA affect the entire skin surface, systemic therapy enhances the contrast between normal skin, which turns darker than usual, and white, vitiliginous skin. Use of sunscreen on normal skin may minimize contrast while preventing sunburn.
Topical class I glucosteroid ointments may be used for single or small macules. Monitor patients on this therapy for skin atrophy or telangiectasia development.
Depigmentation therapy is suggested for patients with vitiligo affecting more than 50% of the body surface. A cream containing 20% monobenzone permanently destroys pigment cells in unaffected areas of the skin and produces a uniform skin tone. This medication is applied initially to a small area of normal skin once daily to test for unfavorable reactions such as contact dermatitis. In the absence of adverse effects, the patient begins applying the cream twice daily to those areas he wishes to depigment first. Eventually, the entire skin may be depigmented to achieve a uniform color. Note: Depigmentation is permanent and results in extreme photosensitivity. Patients may wish to take daily B-carotene to impart an off-white color to the chalk-white skin.
Commercial cosmetics may also help de-emphasize vitiliginous skin. Some patients prefer dyes because these remain on the skin for several days, although the results aren’t always satisfactory. Although often impractical, complete avoidance of exposure to sunlight through the use of screening agents and protective clothing may minimize vitiliginous lesions in whites.
Special considerations
❑ Instruct the patient to use psoralen medications three or four times weekly. (Note: Systemic psoralens should be taken 2 hours before exposure to sun; topical solutions should be applied 30 to 60 minutes before exposure.) Warn him to use a sunscreen (sun protection factor [SPF] 8 to 10) to protect both affected and normal skin during exposure and to wear sunglasses after taking the medication. If periorbital areas require exposure, tell the patient to keep his eyes closed during treatment.
❑ Suggest that the patient receiving depigmentation therapy wear protective clothing and use a sunscreen (SPF 15). Explain the therapy thoroughly, and allow the patient plenty of time to decide whether to undergo this treatment. Make sure he understands that the results of depigmentation are permanent and that he must thereafter protect his skin from the adverse effects of sunlight.
❑ Caution the patient about buying commercial cosmetics or dyes without trying them first because some may not be suitable.
Pediatric tip For the child with vitiligo, modify repigmentation therapy to avoid unnecessary restrictions. Tell parents to give the initial dose of psoralen medication at 1 p.m. and then let the child go out to play as usual. After this, medication should be given 30 minutes earlier each day of treatment, provided the child’s skin doesn’t turn more than slightly pink from exposure. If marked erythema develops, parents should discontinue treatment and notify the physician. Eventually, the child should be able to take the medication at 9:30 a.m. and play outdoors the rest of the day without adverse effects. Tell the parents the child should wear clothing that permits maximum exposure of vitiliginous areas to the sun.
❑ Remind patients undergoing repigmentation therapy that exposure to sunlight also darkens normal skin. After being exposed to UVA for the prescribed amount of time, the patient should apply a sunscreen if he plans to be exposed to sunlight also. If sunburn occurs, advise the patient to discontinue therapy temporarily and to apply open wet dressings (using thin sheeting) to affected areas for 15 to 20 minutes, four or five times daily or as necessary for comfort. After application of wet dressings, allow the skin to air dry. Suggest application of a soothing lubricating cream or lotion while the skin is still slightly moist.
❑ Reinforce patient teaching with written instructions.
❑ Be sensitive to the patient’s emotional needs, but avoid promoting unrealistic hope for a total cure.
Pictures
Book Source Details
- Book Title: Professional Guide to Diseases (Eighth Edition)
- Author(s): Springhouse
- Year of Publication: 2005
- Copyright Details: Professional Guide to Diseases (Eighth Edition), Copyright © 2005 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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