Ex Vivo Detection of SARS-CoV-2 Spike Protein in Human Hair Follicles and Potential Link to Telogen Effluvium

The study explores the potential link between SARS-CoV-2 infection and telogen effluvium (TE) by analyzing human hair follicles (HFs) for viral entry proteins ACE2 and TMPRSS2. Ex vivo experiments showed the presence of viral nucleocapsid protein and apoptotic markers in outer root sheath (ORS) keratinocytes, suggesting direct viral effects on HF epithelial cells. ACE2 and TMPRSS2 were found in specific HF layers, supporting the hypothesis that SARS-CoV-2 may directly infect HFs, potentially contributing to COVID-19-associated TE. Although the study indicates a potential interaction of viral proteins with epithelial cells, it remains unclear if this involves productive infection. The findings suggest that SARS-CoV-2–induced follicular damage could initiate TE, highlighting the need for further research into patient-specific vulnerability and therapeutic approaches.