candidiasis is an opportunistic fungal infection caused by yeasts of the genus Candida, primarily Candida albicans, which can affect the skin, mucous membranes, and internal organs. It is distinguished from dermatophytosis (tinea), which is caused by molds that require keratin for growth, whereas Candida species are dimorphic fungi that can thrive in warm, moist mucosal environments. The underlying mechanism involves the overgrowth of these yeasts—which are normally part of the physiological commensal flora of the gastrointestinal and genitourinary tracts—when the host’s local or systemic immune defenses are compromised or when normal bacterial flora is disrupted by broad-spectrum antibiotics. While colonization is physiological and asymptomatic, pathological overgrowth leads to tissue invasion and inflammation. The most commonly encountered clinical forms in coding include oral thrush or candidal stomatitis (B37.0), vulvovaginal candidiasis (B37.3), candidal cystitis (B37.41), and severe systemic forms like candidal sepsis/candidemia (B37.7). It is commonly confused with bacterial vaginosis or oral leukoplakia; the key difference is that candidiasis is a fungal infection often presenting with curdy white discharge or easily scraped-off white mucosal plaques revealing erythematous bases, whereas bacterial vaginosis is a polymicrobialbacterialdysbiosis and leukoplakia consists of precancerous, non-scrapable white patches.
Noun-forming suffix — “morbid state or condition of”
The word entered English in the 1940s as candidiasis (noun), replacing the older term moniliasis, derived from Modern Latin Candida (the genus name, coined in 1923 by botanist Christine Marie Berkhout), from Latin candidus — literally “condition of the white (fungus).” The adjective form candidal appeared shortly after to describe lesions or infections associated with the yeast. The root candid- (“white”) connects candidiasis to the entire -candid- family: Candida albicans (white yeast that is white [albicans]), candidemia (white yeast in the blood), and candiduria (white yeast in the urine). The suffix -iasis is highly productive in medical terminology for parasitic or infectious conditions, appearing in amebiasis, trichomoniasis, and giardiasis.
🔀 ALIASES / ALTERNATE TERMS
Candidal(adjective form — e.g., “candidal vaginitis,” “candidal stomatitis,” “candidal intertrigo”)
Yeast infection(lay term; most commonly used by patients to describe vulvovaginal or cutaneous presentations)
Thrush(clinical synonym specifically used for oral/oropharyngeal candidiasis; common in pediatrics and otolaryngology)
Moniliasis(historical/older clinical synonym; derived from the former genus name Monilia, now obsolete but occasionally seen in older literature)
Vulvovaginal candidiasis (VVC)(anatomic subtype; fungal infection of the female lower genital tract; B37.3)
Candidemia(systemic form; presence of Candida species in the blood, often healthcare-associated; B37.7)
Antibiotic-induced candidiasis(etiologic subtype; overgrowth resulting from the eradication of competing normal bacterial flora by broad-spectrum antibiotics)
Immunocompromised-associated candidiasis(etiologic subtype; opportunistic infection seen in HIV/AIDS, chemotherapy, or chronic corticosteroid use)
Esophageal candidiasis(organ/tissue-specific form; extension of oral thrush into the esophagus, an AIDS-defining illness; B37.81)
Candidal cystitis(organ/tissue-specific form; fungal infection of the bladder, common in catheterized patients; B37.41)
Candidal intertrigo(organ/tissue-specific form; infection of skin folds such as inframammary or inguinal regions; B37.2)
🔗 RELATED TERMS
Dermatophytosis — the opposite/alternative fungal category to candidiasis; caused by keratinophilic molds (tinea/ringworm) rather than dimorphic yeasts, affecting only the superficial keratinized layers of skin, hair, and nails without mucosal involvement.
Fungemia — shares the fungal disease process; a broader term for any fungi in the blood, whereas candidemia is specifically Candida species.
Bacterial vaginosis (BV) — a polymicrobial dysbiosis of the vaginal flora (N76.0) that is often clinically confused with vulvovaginal candidiasis, but is characterized by a thin, grayish discharge and a “fishy” odor rather than thick, white, curdy discharge.
Oral leukoplakia — a potentially malignant disorder presenting as white patches of the oral mucosa (K13.21) that, unlike oral candidiasis, cannot be rubbed or scraped off.
Immunosuppression — the physiological state or mechanism (e.g., loss of T-cell mediated immunity) that allows commensal Candida to become an opportunistic pathogen.
Opportunistic — adjective describing infections that take advantage of a weakened immune system or altered microbiome to cause disease.
Biofilm formation — the cellular/molecular mechanism by which Candida species adhere to medical devices (like Foley catheters or central lines), making them highly resistant to standard antifungal therapies.
HIV disease / AIDS — acquired immunodeficiency syndrome (B20), where esophageal or recurrent mucosal candidiasis serves as a hallmark opportunistic infection and AIDS-defining condition.
Diabetes mellitus — systemic metabolic disease (E08-E13) strongly associated with recurrent candidiasis due to elevated tissue glucose levels promoting yeast growth and impaired neutrophil function.
Diaper dermatitis — inflammatory skin condition in infants (L22) frequently complicated by secondary Candida infection due to the warm, moist, occluded environment.
KOH preparation — primary diagnostic laboratory test where potassium hydroxide is used to dissolve human cells in a scraping or swab, revealing the characteristic budding yeasts and pseudohyphae of Candida.
Infectious agent detection by nucleic acid (DNA or RNA); Candida species, quantification
⚠️ Coding Note: For inpatient profee coding, sequencing is critical when [[candidiasis]] is associated with an underlying systemic disease. If the patient has HIV/AIDS and presents with esophageal candidiasis (an AIDS-defining illness), sequence B20 (Human immunodeficiency virus [HIV] disease) first, followed by B37.81. In urology, be cautious with “candiduria” (yeast in the urine); asymptomatic colonization in a catheterized patient is often not clinically significant and should not be coded as B37.41 (Candidal cystitis) unless the provider explicitly documents active infection or initiates targeted systemic/bladder irrigationantifungal therapy. A common undercoding issue occurs with candidemia—if the provider documents “candidemia” but the patient meets sepsis criteria, query the provider to clarify if the patient has “candidal sepsis” (B37.7), as candidemia alone defaults to the same code but capturing the systemic inflammatory response may affect severity of illness (SOI) and risk of mortality (ROM) metrics. Always ensure the specific anatomic site (e.g., B37.0 for oral, B37.3 for vaginal) is coded rather than B37.9 (unspecified) to support medical necessity for prescribed antifungals.