Fungal infections are therefore more common and serious in people taking long-term antibiotic drugs (which destroy the bacterial competition) and in those whose immune systems are suppressed by immunosuppressant drugs, corticosteroid drugs, or by a disorder such as AIDS. Such serious fungal infections are described as opportunistic infections. Some fungal infections are more common in people with diabetes mellitus.
Fungal infections can be classified into superficial (affecting skin, hair, nails, inside of the mouth, and genital organs); subcutaneous (beneath the skin); and deep (affecting internal organs).
The main superficial infections are tinea (including ringworm and athlete’s foot) and candidiasis (thrush), both of which are common. Subcutaneous infections, which are rare, include sporotrichosis and mycetoma. Deep infections are uncommon but can be serious and include aspergillosis, histoplasmosis, cryptococcosis, and blastomycosis. The fungal spores enter the body by inhalation.
Treatment of fungal infections is with antifungal drugs, either used topically on the infected area or given by mouth for generalized infections.