Tinea versicolor is caused by which organism?

Tinea versicolor is caused by which organism?

• A. Candida albicans
• B. Trichophyton rubrum
• C. Sporothrix schenckii
• D. Malassezia sp

Answer: (D)

Tinea versicolor is produced by Malassezia species, a lipophilic yeast that lives in the outer skin layers and overgrows in warm, humid conditions. This organism is distinct from Candida albicans, which typically causes mucosal candidiasis, and from dermatophytes like Trichophyton rubrum that invade keratinized tissues to cause classic tinea infections of the scalp, body, feet, or nails. It’s also not Sporothrix schenckii, a dimorphic fungus that causes a subcutaneous infection after trauma. In the lab, skin scrapings treated with potassium hydroxide often reveal the characteristic appearance of Malassezia: yeast cells with short hyphae, described as spaghetti and meatballs. The pigment changes you see on the skin—hypopigmented or hyperpigmented macules on the trunk and shoulders—are due in part to azelaic acid produced by the yeast, which inhibits tyrosinase and melanin production. Thus, the organism responsible for tinea versicolor is Malassezia species.

Tinea versicolor is produced by Malassezia species, a lipophilic yeast that lives in the outer skin layers and overgrows in warm, humid conditions. This organism is distinct from Candida albicans, which typically causes mucosal candidiasis, and from dermatophytes like Trichophyton rubrum that invade keratinized tissues to cause classic tinea infections of the scalp, body, feet, or nails. It’s also not Sporothrix schenckii, a dimorphic fungus that causes a subcutaneous infection after trauma.

In the lab, skin scrapings treated with potassium hydroxide often reveal the characteristic appearance of Malassezia: yeast cells with short hyphae, described as spaghetti and meatballs. The pigment changes you see on the skin—hypopigmented or hyperpigmented macules on the trunk and shoulders—are due in part to azelaic acid produced by the yeast, which inhibits tyrosinase and melanin production.

Thus, the organism responsible for tinea versicolor is Malassezia species.