Dermatophytosis (tinea) is a group of superficial fungal infections usually classified according to their anatomic location. Dermatophytosis may affect the scalp (tinea capitis), the bearded skin of the face (tinea barbae), the body (tinea corporis, occurring mainly in children), the groin (tinea cruris, or jock itch), the nails (tinea unguium, also called onychomycosis), and the feet (tinea pedis, or athlete's foot). These disorders vary from mild inflammations to acute vesicular reactions.
Tinea infections are prevalent in the United States and are usually more common in males than in females. Although remissions and exacerbations are common, with effective treatment, the cure rate is very high. About 20% of infected people develop chronic conditions.
Tinea infections result from dermatophytes (fungi) of the genera Trichophyton, Microsporum. and Epidermophyton. Transmission can occur directly (through contact with infected lesions) or indirectly (through contact with contaminated articles, such as shoes, towels, or shower stalls). Warm weather and tight clothing encourage fungus growth.
Signs and Symptoms
The most common clinical sign associated with dermatophytosis is a circular area of hair loss (alopecia). Other clinical signs include scaling, redness (erythema), darkening of the skin (hyperpigmentation), and itchiness.
Potassium hydroxide test and microscopic examination of lesion scrapings usually confirm tinea infection. Wood's light examination may confirm some types of tinea capitis. Culture of the affected area may help to identify the infecting organism.
Local tinea infections usually respond to topical antifungal agents, such as imidazole cream or oral griseofulvin for infections of the skin and hair. Oral terbinafine or itraconazole is helpful in nail infection. Topical therapy is effective for tinea capitis; oral griseofulvin for 1 to 3 months is the treatment of choice. In addition to imidazole, other antifungals include naftifine, ciclopirox, terbinafine, haloprogin, and tolnaftate. Topical treatment should continue for 2 weeks after lesions resolve.
Supportive measures include application of open wet dressings, removal of scabs and scales, and administration of keratolytics such as salicylic acid to soften and remove hyperkeratotic lesions of the heels or soles.
The skin should be kept dry, since moist skin favors the growth of fungi. Dry the skin carefully after bathing and let it dry before dressing. Loose-fitting underwear is recommended. Socks should be changed daily. Sandals or open-toed shoes may be beneficial. Talc or other drying powders may also be helpful.
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