[Scopulariopsis brevicaulis : The "arsenic fungus"-a difficult-to-treat pathogen].

Scopulariopsis (S.) brevicaulis is a human pathogenic hyalohyphomycete from the Microascaceae family, which plays a role in dermatological practice, particularly as a pathogen of onychomycosis. Less commonly, it is the causative agent of skin mycoses, even in immunocompetent patients, as well as of systemic infections. In culture, brown-cinnamon colored colonies with a powdery surface are observed. Conidia are produced in annellid chains, have a truncated base, and a spiny-verrucous surface at maturity. S. brevicaulis can also be differentiated using some commercial polymerase chain reaction (PCR) kits. Since the pathogen also frequently occurs in the environment, its clinical relevance must be confirmed by further investigations, especially by histopathology and/or repeated detection. Therapy is difficult because there is sometimes intrinsic resistance to common antifungal agents. The significance of resistance testing is still limited due to a lack of standardization. Furthermore, differences in pathogenicity between individual isolates appear to exist. According to the guidelines, topical therapy is recommended for onychomycosis by S. brevicaulis, and systemic/topical combined therapy for mixed infections (dermatophyte + S. brevicaulis). S. brevicaulis is also of environmental toxicological importance because it can release volatile arsenic derivatives from arsenic-containing compounds in the presence of carbohydrates, which has also led to the name "arsenic fungus".