Tinea versicolor
Beth G ****stein, MD
Adam O ****stein, MD, MPH
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INTRODUCTION — Tinea versicolor is a common superficial infection caused by the organism Pityrosporum orbiculare (also known as Malessezia furfur, Pityrosporum ovale, or Malassezia ovalis). This organism is a saprophytic yeast that is part of the normal skin flora. A number of factors may trigger conversion to the mycelial or hyphal form that is associated with clinical disease, including hot and humid weather, use of oils, hyperhidrosis, and immunosuppression, among others [1]. (See "Malassezia infection").
Tinea versicolor responds well to medical therapy, but recurrence is common and long-term prophylactic therapy may be necessary.
CLINICAL FEATURES — Versicolor refers to the variety and changing shades of colors present in this disease. Lesions can be hypopigmented, light brown, or salmon colored macules (show picture 1 and show picture 2). A fine scale is often apparent, especially after scraping. Individual lesions are typically small, but frequently coalesce. Lesions are limited to the outermost layers of the skin, most commonly on the upper trunk and extremities, and less often on the face and intertriginous areas. While most patients are asymptomatic, some complain of mild pruritus, and many are concerned about cosmesis or potential contagion.
Tinea versicolor occurs most commonly in adolescents and young adults, with the highest incidence in tropical climates. It also occurs commonly in patients who are immunosuppressed [2]. It is most evident in the summer because the organism produces azelaic acid, which inhibits pigment transfer to keratinocytes, thereby making infected skin more demarcated from uninfected, evenly pigmented skin.
DIAGNOSIS — The diagnosis of tinea versicolor is confirmed by direct microscopic examination of scale with 10 percent potassium hydroxide (KOH). (See "Dermatologic procedures", section on KOH preparation). Classically both hyphae and spores are evident in a pattern that is often described as "spaghetti and meatballs" (show picture 3).
The differential diagnosis includes seborrhea, eczema, pityriasis rosea, and secondary syphilis. Seborrheic lesions are more frequently confined to the central trunk, are more erythemetous, and have thicker scales. With eczema, patients usually have more scaling, pruritus, and involvement of the extremities. Patients with pityriasis usually have a herald patch, more peripheral scale around border lesions, confinement of lesions to the central trunk, and the lesions do not show hyphae on KOH prep. (See "Pityriasis rosea"). Secondary syphilis often involves the hands and feet, and the lesions do not show hyphae on KOH prep. (See "Early syphilis").
TREATMENT — Topical antifungal therapy is the treatment of choice for patients with limited disease. Virtually any topical anti-yeast preparation can be used with cure rates exceeding 70 to 80 percent (show table 1) [3-5]. Treatment usually continues for two weeks. Patients should be advised that healing will continue after active treatment stops; resumption of more even pigmentation may take months after the completion of successful treatment.
Oral medications are more convenient for patients with extensive disease and also may be more effective in patients with recalcitrant infection. Again, most oral antifungal agents, with the exception of griseofulvin or terbinafine, may be used [6]. Ketoconazole as a single dose of 400 mg or 200 mg daily for five days achieves cure rates greater than 90 to 95 percent at four weeks [7]. Ketoconazole can cause GI upset (nausea, vomiting, and diarrhea) and headache and dizziness when administered orally; hepatotoxicity also has been reported, although rarely with the short duration of therapy used for tinea versicolor [7]. (See "Imidazoles"). Fluconazole (single 400 mg dose) and itraconazole (single 400 mg dose) are also effective, with similar cure rates [8-10].
Some patients may prefer to use ketoconazole 2% shampoo in a single application or daily for three days. In a randomized, controlled trial, approximately 70 percent of patients utilizing this therapeutic approach remained "cured" one month after treatment [3].
In addition to the above measures, patients should be advised to avoid skin oils, and that suntanning will make the condition more apparent. Failure to respond to the above therapies should prompt reassessment of the diagnosis or referral to a dermatologist. Resistance to therapy, frequent recurrence, or widespread disease should prompt consideration of an immunodeficient state (show table 2).
PREVENTION — Patients who experience frequent recurrences of tinea versicolor (particularly immunosuppressed individuals) can successfully prevent recurrences with use of topical or oral preventive therapy, particularly during warm weather. Prophylaxis with topical selenium sulfide solution 2.5 percent (Selsun) applied to the entire body for ten minutes every two to three weeks is effective, as is oral ketoconazole (400 mg once per month) [1] and itraconazole (200 mg twice daily for one day per month) [11].
16-08-2006, 03:26 PM
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