Pathogenesis and Etiology Candida albicans is a ubiquitous, usually saprophytic, yeast that can become pathogenic if a favorable environment or the host's weakened defenses allow the organisms to proliferate. The interrelation of these factors and the mechanisms that increase susceptibility to infection are discussed in Ch. 151. Specifically, intertriginous and mucocutaneous areas where heat and maceration provide a fertile environment are most susceptible. Symptoms and Signs Intertriginous infections, the most common type, appear as well-demarcated, erythematous, sometimes itchy, exudative patches of varying size and shape. Perianal candidiasis produces white macerated pruritus ani.
Candidal paronychia begins around the nail as a painful red swelling that later develops pus.
It may result from improperly performed manicures and is common in kitchen workers and others whose hands are continually in water. In immunodeficient patients, other more typical candidal lesions or systemic candidiasis may also occur. Diagnosis Candida can be shown by finding yeast and pseudohyphae in gram-stained specimens or in potassium hydroxide mounts of scrapings from a lesion. Because Candida is a commensal of humans, isolation of the organism in culture from the skin, mouth, vagina, urine, sputum, or stool should be interpreted cautiously. To confirm the diagnosis, a characteristic clinical lesion, exclusion of other causes, and, at times, histologic evidence of tissue invasion are needed.