Black piedra

Overview

Black piedra
ICD-10	B36.3
ICD-9	111.3
DiseasesDB	31872
eMedicine	derm/788
MeSH	D010854

Black piedra is a form of piedra caused by Piedraia hortae.

Terbinafine has been used in the treatment.

Differential Diagnosis

Black piedra should be differentiated from other diseases presenting as red, pruritic, annular, scaly rash. The differentials include the following:

Name of superficial infection	Clinical presentation	Extension to hair follicle	Fungus(i)	Systemic disease	KOH preparations	Morphology in tissue sections
Tinea or ringworm	Round lesions with scaly border, accompanied by pruritis and burning	Yes; when suppurative known as kerion, when chronic known as Majocchi's granuloma	Dermatophytes (Epidermophyton spp., Trichophyton spp., Microsporum spp.)	Very rare but can invade the dermis and soft tissues, causing mycetomas	Hyphae with or without septations	Hyphae cannot be visualized in the keratin with H&E, special stains are needed
Tinea versicolor	Hypo and hyperpigmentation in patients with oily and sweaty skin, fine scales when scratching	Yes, known as Pityrosporum folliculits	Malassezia spp.	Systemic infections may occur in premature neonates receiving parenteral nutrition and in other immunosuppressed hosts	Yeasts and hyphae (“spaghetti and meat balls”)	Faintly basophilic hyphae in the stratum corneum
Tinea nigra	Brown to black macule, usually on palms, with some scaling	No	Phaeoannellomyces werneckii	Not described	Darkly pigmented, septated, and branching hyphae	Pigmented hyphae in the stratum corneum
White piedra	Creamy-white, small, soft nodules in hair shafts	No	Trichosporon spp.	Immunosuppressed patients may have lung infiltrates, renal involvement, and fungemia	Septate hyphae perpendicular to hair shaft	Not used for diagnosis
Black piedra	Hard dark nodules in hair shafts	No	Piedraia hortae	Not described	Collections of crescent ascospores surrounded by pigmented hyphae	Not used for diagnosis
Superficial candidiasis	Intertrigo, chronic paronychia, onychodystrophy, cheilitis	Yes	Candida spp.	Yes, particularly in patients with AIDS and depending on the level of immunosuppression	Yeasts, pseudohyphae may be observed	Fungal elements may be seen through the biopsy, vascular invasion must be determined

See also

• Tinea nigra

Gallery

• 
  Under a relatively-low magnification of 100X, this photomicrograph reveals some of the pathologic morphology displayed by a primate hair shaft indicative of the disease known as, “black piedra”, also known as “trichosporosis”, which is caused by the fungal organism, Piedraia hortae. From Public Health Image Library (PHIL).
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  This is a photomicrograph of a hair shaft with a condition called “black piedra” due to Piedraia hortae. From Public Health Image Library (PHIL).
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  This is a photomicrograph of the mycelium of the fungus Piedraia hortae, magnified 475X. From Public Health Image Library (PHIL).
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  This is a plate culture of Piedraia hortae, strain A272. From Public Health Image Library (PHIL).