Dermatophytosis

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), or the feet (tinea pedis, or athlete’s foot). These disorders vary from mild inflammations to acute vesicular reactions.

Causes

Tinea infections are caused by 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 or surfaces, such as shoes, towels, or shower stalls). Some cases result from contact with contaminated animals or soil. Warm weather, humidity, and tight clothing encourage fungus growth.

Complications

Hair or nail loss and secondary bacterial or candidal infections, resulting in inflammation, itching, tenderness, and maceration, are common complications of tinea infection. About 20% of infected people develop chronic conditions.

Assessment Findings

Tinea lesions vary in appearance and duration. Inspection of a patient with tinea capitis may expose small, spreading papules on the scalp that may progress to inflamed, pus-filled lesions (kerions). Patchy hair loss with scaling may be visible. Tinea barbae appears as pustular folliculitis in the bearded area.

In patients with tinea corporis, inspection and palpation reveal flat skin lesions at any site except the scalp, bearded skin, or feet. These lesions may be dry and scaly or moist and crusty; as they enlarge, their centers heal, producing the classic ring-shaped appearance.

In patients with tinea cruris, inspection and palpation reveal raised, sharply defined, itchy red lesions in the groin that may extend to the buttocks, inner thighs, and external genitalia.

Tinea unguium starts at the tip of one or more toenails (fingernail infection is less common). Inspection reveals gradual thickening, discoloration, and crumbling of the nail, with accumulation of subungual debris. Eventually, the nail may be completely destroyed.

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