Nodules on the Hair: A Rare Case of Mixed Piedra
Piedra is a superficial fungal infection of the hair shaft characterized by nodules along the hair shaft. Black piedra affects the scalp hair more frequently than white piedra. The occurrence of both types of piedra simultaneously in a patient is extremely rare. Published in the International Journal of Trichology, the authors describe a rare case of mixed piedra of scalp hair.

A 40-year-old married female 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.

Examination 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 the treatment of pediculosis capitis.

Case pointers:-
• Occurrence of piedra may be influenced by climatic conditions. Both black-and-white piedra occur predominantly in humid tropical and semi-tropical areas (Africa, South America, and Asia).

• However, white piedra has been reported from temperate climatic areas like Europe, USA and Japan as well. Common sources of infection in both types are stagnant water and soil. Trichosporosis has also been found in vegetable matter, some plants and bird droppings and occasionally in wild mammals.

• Sexual transmission has been reported in both types of piedra.

• Factors such as poor hygiene, long hair, excessive use of hair oil, cultural practices such as tying of veil, especially when done on wet hair may contribute to the infection.

• Piedra is best treated by shaving or clipping the hair, but this may not be considered cosmetically or socially acceptable, particularly by women.

• Topical antifungal azole lotions/shampoos are effective. Oral antifungals such as terbinafine and itraconazole have been used successfully in cases resistant to topical medication.

• Patients should be counseled regarding good hygiene, avoidance of use of shared combs and clips, discarding or disinfecting underclothes (in genital piedra) in order to prevent recurrence.

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