RESUMEN
BACKGROUND: The spreading of the SARS-CoV-2 Omicron variant is probably due to its increased transmissibility and ability to escape from neutralising antibodies. Cutaneous manifestations have been reported after infection with the Omicron strain, consisting mainly of generalised urticarial eruption and prickly heat rash, also known as miliaria, that can persist for several days. Here the impact of Omicron SARS-CoV-2 on skin was investigated. METHODS: The case series of 10 patients with SARS-CoV-2 Omicron variant-related cutaneous manifestations were described; moreover, skin derived cells were challenged in vitro with SARS-CoV-2 Omicron variant. RESULTS: The main clinical cutaneous features observed were urticarial lesions lasting more than 24 h, mainly involving the trunk and sometimes extending to the extremities, and miliaria presenting with clusters of small sweat-filled vesicles, sometimes surrounded by slight erythema. HaCaT keratinocytes, BJ fibroblast cell lines and outer root sheath (ORS) keratinocytes were not susceptible to SARS-CoV-2 Omicron variant infection; they also did not present any evident cytopathic effect or modification of cells viability. CONCLUSION: Our findings suggests that, despite the high number of nucleotide mutations in the spike protein of SARS-CoV-2 Omicron variant, responsible to the higher transmissibility of this virus, and the increased reports of cutaneous manifestation in COVID-19 affected patients, the virus is not able to directly infect and damage the keratinocytes and fibroblasts, thus suggesting an indirect virus-induced activation of the immune system as the major pathogenetic driver.