Chronic mucocutaneous candidiasis is an immune deficiency disorder primarily due to T cell dysfunction characterized by persistent candidal infection of mucous membrane, skin, scalp and nails.

Chronic mucous membrane candidiasis has an onset in infancy or childhood; the primary affected site is the oral cavity; however, lesions may occur on trunk, hands, feet and scalp.

Although the initial lesions are identical to the ones seen in the general population, over time patients with CMC characteristically develop unique disfiguring lesions. The chronic infection and the large disfiguring nature of keratotic lesions are key characteristics of CMC.