disease has infectious agent piedra black piedra https://www.malacards.org/card/black_piedra icd11.foundation:1990974193 MEDGEN:452132 ICD9:111.3 ICD10CM:B36.3 A superficial mycosis that is caused by Piedraia hortae and is manifested by a small firm black nodule involving the hair shaft. DOID:12711 MONDO:0005669 UMLS:C0153249 SCTID:33666009 superficial mycosis Piedraia hortae