Nodules on the Hair: A Rare Case of Mixed Piedra
A 40-year-old married female hailing from West Bengal came with the complaints of difficulty in combing hair and blackish small nodules attached to her scalp hair. There was no history of hair loss. There was no family history of similar complaints. Patient gave a history of similar symptoms 5 years back, which had resolved by using antifungal shampoo for 3 months.\nExamination of scalp hair revealed multiple discrete firms to hard, brown to black tiny nodules attached to hair shaft. These nodules were distributed irregularly along the length of hair shaft []. When pulled between the fingers, these hairs gave a raspy sensation. Patient also had concurrent nits suggestive of pediculosis capitis. Examination of underlying scalp was normal. Axillary and pubic hair were normal. A provisional diagnosis of black piedra was made. 10% potassium hydroxide (KOH) examination was done from multiple nodules, which surprisingly revealed two different set of findings. Examination of black colored nodule revealed a concretion forming a collar around normal hair shaft, which was made up of filamentous hyphae, held together by cement like substance with spores seen at the edges of the nodule []. Crushing of nodule by gentle pressure revealed presence of brown dematiaceous closely septate hyphae with few chlamydospores on KOH mount []. Culture from black colored nodule on the Sabouraud's dextrose agar at room temperature grew small, compact, blackish conical colonies with velvety surface []. The reverse side of the colonies also revealed black color. One of the colonies, on microscopic examination revealed round, dark brown, globus ascus confirmatory for Piedraia hortae species []. KOH mount of brown colored nodule revealed nondematiaceous, loosely arranged septate hyphae with arthroconidia and blastoconidia []. Culture from the brown colored nodule grew white to cream colored, wrinkled, velvety, dull colonies with a mycelial fringe surrounding the hair shaft []. Lactophenol cotton blue mount from the fungal colonies showed multiple hyaline septate hyphae and arthrospores confirming Trichosporon sp. []. Thus microscopic and culture characteristics confirmed presence of both black-and-white piedra, i.e., mixed piedra. Presence of nits of Pediculus capitis was also confirmed on microscopy []. Patient was advised trimming of her hair and application of 2% ketoconazole lotion once a week for 3 months resulting in disappearance of the nodules. Patient was also treated with 1% permethrin (single application) for treatment of pediculosis capitis.