(Tinea Versicolor)

Pityriasis versicolor (formerly tinea versicolor) is a common superficial yeast infection of the skin characterized by multiple scaling, oval, and patchy macular lesions usually distributed over upper portions of the trunk, proximal areas of the arms, and neck. Facial involvement particularly is common in children. Lesions may be hypopigmented or hyperpigmented (fawn colored or brown). Lesions fail to tan during the summer and during the winter are relatively darker, hence the term versicolor . Common conditions confused with this disorder include pityriasis alba, postinflammatory hypopigmentation, vitiligo, melasma, seborrheic dermatitis, pityriasis rosea, and dermatologic manifestations of secondary syphilis.

Etiology

The cause of pityriasis versicolor is Malassezia species, a group of lipid- dependent yeasts that exist on healthy skin in yeast phase and cause clinical lesions only when substantial growth of hyphae occurs. Moist heat and lipid-containing sebaceous secretions encourage rapid overgrowth.

Epidemiology

Pityriasis versicolor occurs worldwide but is more prevalent in tropical and subtropical areas. Although primarily a disorder of adolescents and young adults, pityriasis versicolor also may occur in prepubertal children and infants. Malassezia species commonly colonize the skin in the first year of life and usually are harmless commensals. Malassezia can be associated with bloodstream infections, especially in neonates receiving total parenteral nutrition with lipids.

The incubation period is unknown.

Diagnosis

The clinical appearance usually is diagnostic. Involved areas are fluorescent yellow under Wood light examination. Skin scrapings examined microscopically in a potassium hydroxide wet mount preparation or stained with methylene blue or May-Grünwald-Giemsa stain disclose the pathognomonic clusters of yeast cells and hyphae ("spaghetti and meatball" appearance). Growth of this yeast on culture requires a source of long-chain fatty acids, which may be provided by overlaying Sabouraud dextrose agar medium with sterile olive oil.

Treatment

Topical Treatment with selenium sulfide as 2.5% lotion or 1% shampoo has been the traditional Treatment of choice. These preparations are applied in a thin layer covering the body surface from the face to the knees for 30 minutes daily for a week, followed by monthly applications for 3 months to help prevent recurrences. In adults, topical ketoconazole 2% shampoo used as a single application daily for 5 days is an effective alternative. Other topical preparations with therapeutic efficacy include sodium hyposulfite or thiosulfate in 15% to 25% concentrations (eg, Tinver lotion) applied twice a day for 2 to 4 weeks. Small focal infections may be treated with topical antifungal agents, such as ciclopirox, clotrimazole, econazole, ketoconazole, miconazole, oxiconazole, or naftifine (see Topical Drugs for Superficial Fungal Infections). Because Malassezia species are part of normal flora, relapses are common. Multiple topical Treatments may be necessary.

Oral antifungal therapy has advantages over topical therapy, including ease of administration and shorter duration of Treatment, but oral therapy is more expensive and associated with a greater risk of adverse reactions. A single dose of ketoconazole (400 mg orally) or fluconazole (400 mg orally) or a 5-day course of itraconazole (200 mg orally, once a day) has been effective in adults. Some experts recommend that children receive 3 days of ketoconazole therapy rather than the single dose given to adults. For pediatric dosage recommendations for ketoconazole, fluconazole, and itraconazole, see Recommended Doses of Parenteral and Oral Antifungal Drugs. These drugs have not been studied extensively in children for this purpose and are not approved by the US Food and Drug Administration for this indication. Exercise to increase sweating and skin concentrations of medication may enhance the effectiveness of systemic therapy. Patients should be advised that repigmentation may not occur for several months after successful Treatment.

Isolation of the Hospitalized Patient

Standard precautions are recommended.

Control Measures

Infected people should be treated.