mycosis, in humans and other animals, an infection caused by any fungus that invades the tissues, causing superficial, subcutaneous, or systemic disease. Many different types of fungi can cause mycosis, and some types, such as Cryptococcus and Histoplasma, can cause severe, life-threatening infections.
Superficial fungal infections, also called dermatophytosis, are confined to the skin and are caused by Microsporum, Trichophyton, or Epidermophyton; athlete’s foot, for example, is caused by Trichophyton or Epidermophyton. Subcutaneous infections, which extend into tissues under the skin, including adjacent structures such as bone and organs, are rare and often chronic. Candidiasis (caused by Candida) may be a superficial infection (e.g., thrush or vaginitis) or a disseminated infection affecting certain target organs, such as the eyes or kidneys. In sporotrichosis (caused by Sporothrix), painful ulcerations and nodules appear in subcutaneous tissues. In systemic fungal infections, fungi may invade normal hosts or immunosuppressed hosts (causing opportunistic infections). Cryptococcosis (caused by Cryptococcus) and histoplasmosis (caused by Histoplasma) are marked by respiratory distress.
Topical antifungal drugs, usually available as creams, liquids, or sprays, are often effective for superficial infections. The antifungal griseofulvin has met with some success in the treatment of superficial mycoses, and amphotericin B and flucytosine have been used in treating subcutaneous and systemic mycoses.