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| Vitiligo |
An acquired, slowly progressive depigmenting condition in small or large areas of the skin due to the disappearance of previously active melanocytes
•Type A is non-dermatomal and widespread. It represents 75% of cases
•Type B is dermatomal or segmental. It represents the remaining 25% of cases
SIGNS AND SYMPTOMS:
•Loss of pigment
•Locally increased sunburning
•Predilection for acral areas and around orifices such as eyes, mouth, anus
•Pruritus (10%)
•Premature graying (35%)
•Koebner's phenomenon (aggravation by trauma)
CAUSES:
Etiology is unclear, but is thought to be an autoimmune reaction to preexisting melanocytes
RISK FACTORS:
•Positive family history
•Autoimmune disorders including hemolytic anemia and adrenal insufficiency
DIFFERENTIAL DIAGNOSIS:
Any condition that causes acquired hypomelanosis, including tinea versicolor, leprosy, lupus erythematosus, pityriasis alba, atopic dermatitis, albinism, alopecia areata, chemical exposure (phenols, arsenic, chloroquine, hydroquinone) steroid exposure, retinoic acid use, tuberous sclerosis, neurofibromatosis, melanocytic nevi (halo nevi), tumor regression of malignant melanoma, piebaldism, hypopituitarism, hyperthyroidism
LABORATORY:
Routine blood and urine studies are usually normal in the absence of associated diseases in adults. In children screen for autoimmune diseases with TSH, CBC, and fasting glucose.
PATHOLOGICAL FINDINGS:
Complete absence of melanocytes in skin biopsy. At the margins one may see a few lymphocytes and large melanocytes with abnormal melanosomes.
DIAGNOSTIC PROCEDURES:
•Examination under Wood's light accentuates the hypopigmented areas, especially in light-skinned individuals
•Skin scraping and a potassium hydroxide (KOH) preparation can be examined microscopically to rule out tinea versicolor
GENERAL MEASURES:
•Sun exposure can accentuate the difference between normal and abnormal skin, so for cosmetic reasons patients may wish to avoid this
•Skin dyes and cosmetics may be used as cover-ups
PATIENT EDUCATION:
•Reassure patient that in absence of associated autoimmune illness the problem is purely cosmetic. Successful cosmetic cover-up is usually quite simple. Some areas offer vitiligo support groups.
•Information available through National Vitiligo Foundation, P.O. Box 6337, Tyler TX 75711; (903)531-0074
DRUG(S) OF CHOICE:
•Localized vitiligo: Begin with a mid-potency steroid cream applied daily for 3-4 months. If no response, advance to high potency steroids. Clobetasol propionate (Temovate) cream applied qd for 2 months (qod on the face). Treatment may be resumed following a 1 to 4 month respite. Alternatively topical psoralens applied in a 1% solution followed in 90 minutes by ultraviolet exposure (UVA). Caution for subsequent exposure to light (sunburn).
•Widespread vitiligo: Oral systemic steroids, e.g., betamethasone 5 mg given 2 days in a row, then held the remainder of the week. This pattern continued for 2-4 months minimizes side effects and is effective in arresting the disease in many patients. Oral trimethylpsoralen or methoxsalen (Oxsoralen-Ultra, 8-MOP) and UVA over a 12-24 month period. Alternatively depigmenting the remaining normal skin with hydroquinone (Benoquin) 20% cream may be elected.
Contraindications:
•Absolute contraindications to use of psoralen compounds: Idiosyncratic reaction to psoralens, photosensitive disease (e.g., systemic lupus erythematosus, albinism, porphyria), invasive squamous cell carcinoma, melanoma, aphakia
•Relative contraindications to use of psoralen compounds: Cardiac disease, hepatic dysfunction, multiple basal cell carcinomas, prior radiation therapy, prior arsenic therapy
Precautions:
•Watch for skin atrophy and telangiectasias when using topical steroids, especially on the face
•Watch for photosensitizers with UVA treatment
•Severe burns possible with topical psoralens. Partially avoided with - 1:10 or 1:50 dilution of psoralens.
•Psoralen plus UVA (PUVA) cannot be used for children less than 12 years of age due to immaturity of the ocular lens
•Patients undergoing PUVA therapy should have a screening ophthalmologic examination to rule out subclinical retinal pigmentary disease that is frequently associated with vitiligo
Significant possible interactions: Other photosensitizers, e.g., tetracyclines and retinoic acid
ALTERNATIVE DRUGS:
Patients with unresponsive localized vitiligo may be candidates for mini-grafting with or without PUVA therapy
FOLLOW UP
PATIENT MONITORING:
•With PUVA therapy, CBC, liver, renal function tests, and an ANA should be done every 6 months.
•With topical steroids, follow at monthly intervals to avoid steroid-atrophy of the skin.
PREVENTION/AVOIDANCE:
•While undergoing all therapies, avoid excessive sun exposure
POSSIBLE COMPLICATIONS:
•Phototoxic reactions ranging from mild to severe with PUVA
•Skin atrophy and telangiectasias with topical steroids
•Contact dermatitis can occur with use of depigmenting agents and cosmetic covers
EXPECTED COURSE AND PROGNOSIS:
•Only 5% spontaneously repigment
•Best results are with PUVA therapy where 70% have repigmentation of head and neck area, less in other body areas. Lower percentages respond to topical therapy
•There is no response in at least 20% of cases, especially long-standing cases
•Once repigmentation occurs it usually persists.
ASSOCIATED CONDITIONS:
•Addison's disease
•Alopecia areata
•Chronic mucocutaneous candidiasis
•Diabetes mellitus
•Hypoparathyroidism
•Melanoma
•Pernicious anemia
•Polyglandular autoimmune syndrome
•Thyroid disorders (hyper- and hypothyroidism) - 30% of patients with vitiligo
•Uveitis
•Halo nevi
PREGNANCY:
•Treatment with topical or oral psoralens is contraindicated
SYNONYMS:
•Hypomelanosis
•Depigmentation
REFERENCES
•Habif T: Clinical Dermatology. 3rd Ed. St Louis, Mosby, 1996
•Fitzpatrick TB, et al: Color Atlas and Synopsis of Clinical Dermatology. 3rd Ed. New York, McGraw-Hill, 1997
•Goldstein A, Goldstein B: Practical Dermatology. 2nd ed. St. Louis, Mosby, 1997.Labels: Depigmentation, Hypomelanosis |
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hello... hapi blogging... have a nice day! just visiting here....