Fungal infections of the hand

Fungal infections of the upper extremity are of four main types--cutaneous, subcutaneous, deep, and systemic. Cutaneous infections are caused by organisms capable of metabolizing keratin. They involve the skin and nails but do not penetrate deeper. Most cutaneous infections respond to topical or local therapy. Subcutaneous infections (at least in North America) are most commonly caused by Sporothrix schenckii. Diagnosis is often delayed because associated secondary bacterial colonization may be mistaken for the primary infectious agent. Treatment with systemic antifungal agents is usually successful. Deep infections are usually caused by direct inoculation or, rarely, hematogenous spread of fungi. Systemic fungal infections are of two types--those that occur in normal hosts and those that occur primarily in immunocompromised patients. For both deep and systemic fungal infections, permanent impairment is likely. Diagnosis of deep and systemic fungal infections is often delayed. Treatment of such infections usually requires a combination of surgical excision and systemic antifungal therapy.