An otherwise healthy 23-year-old woman presented with facial symmetrical erythema and slight itching lasting 4 days. Symptoms developed after wearing a KN95 (FFP2 equivalent) mask for 2 days to prevent contracting SARS-CoV-2. One day before, the patient had consulted the

BackgroundSchizophyllum commune, a basidiomycetous fungus, is a common invader of rotten wood. This fungus rarely causes mycotic disease in humans, especially cutaneous infection. In this paper, we describe the first case of cutaneous granuloma caused by S. commune in a Chinese woman.Case presentationA 25-year-old female with a two-year history of erythema, papules, nodules, and scales on her sole of left foot was presented to our outpatient center. Samples were obtained by the scraping of lesion and for light microscopy. Hyphae were observed by microscopic examination. We carried out a skin tissue biopsy, which showed multiple granulomatous nodules. Biopsy specimens were also inoculated onto media. After being cultured on SDA at 27 °C for 7 days, spreading-woolly-white colonies grew on the inoculation sites of media containing chloramphenicol only and there,s no other colonies grew. S. commune was identified by morphology methods, biochemical tests, and PCR sequencing. Pathological findings also aided in diagnosing cutaneous fungal granuloma. Oral itraconazole was applied. After 1 month of therapy, rashes on her left foot and pain were improved.ConclusionWe describe the first case of cutaneous granuloma caused by Schizophyllum commune, which illustrates the importance of recognizing uncommon pathogenic fungal infections.

We would like to acknowledge all staff working in the Contact Eczema and Immunoallergic Diseases Department, especially the specialized nurse Victor Alfredo Cassini Gómez de Cádiz.

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