Mycosis

Mycosis is the medical term for a fungal infection, in which fungi invade and damage the tissues of a person or animal. It differs from mycotoxicosis, poisoning by fungal toxins in food, and from allergy to mold spores. Mycoses are grouped by depth. Superficial and cutaneous mycoses involve the skin, hair and nails; the commonest are tineas, or ringworm, caused by dermatophyte molds that feed on keratin, including athlete's foot and fungal nail infection. Subcutaneous mycoses, such as sporotrichosis, enter deeper tissue through a wound. Systemic mycoses reach internal organs, usually after spores are inhaled, as in histoplasmosis and coccidioidomycosis.

Many serious mycoses are opportunistic: fungi that normally live harmlessly on the body or in the environment, such as Candida, Aspergillus and Pneumocystis, cause severe disease when immunity is weakened by HIV, cancer treatment, transplant drugs or long hospital stays. Diagnosis relies on microscopy, often of skin scrapings cleared with potassium hydroxide, along with culture, biopsy and tests for fungal antigens or DNA. Treatment uses antifungal drugs such as azoles, terbinafine and amphotericin B. Because fungal cells are eukaryotic like human cells, few drug targets are unique to them, and resistance, as in Candida auris, is growing.