A young adult presents with multiple discrete, soft, white-to-tan nodules firmly attached along the hair shafts of the axillary and pubic hair. KOH examination of the nodule reveals hyaline hyphae and arthrospores. Culture grows cream-coloured, wrinkled colonies. The causative organism is:

• A Piedraia hortae
• B Malassezia globosa
• C Corynebacterium tenuis
• D Trichosporon asahii (beigelii) ✓

Explanation

White piedra is caused by Trichosporon species (T. asahii, formerly beigelii), producing soft white nodules on axillary, pubic and beard hairs; KOH shows hyaline hyphae and arthroconidia, and colonies are cream-coloured and wrinkled. Piedraia hortae causes black piedra, with hard, dark nodules containing asci. Corynebacterium tenuis causes trichomycosis axillaris, which forms adherent concretions but is bacterial and not composed of fungal hyphae.

Reference: Jawetz, Melnick and Adelberg's Medical Microbiology, 28th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.