Background: There have been few reports of cutaneous skin lesions in severe COVID-19 hospitalized patients which exhibit different behavior compared to outpatients. Furthermore, a notable lack of rigorous studies exits. In this study we included patients with generalized rash during the first wave of the pandemic for characterization.Methods: Hospitalized patients with severe confirmed pulmonary COVID-19 infection and a generalized cutaneous rash during the first wave in March-May 2020 were included. The study received approval from the ethics committee. Clinical presentation, histo-logical examination, blood test, and complete blood interleukin profile were assessed. Special immunohistochemical investigations were conducted. Long term follow-up of the patient was performed throuhg a phone call 24 months later. Results: A total 28 patients were studied and classified by histological examination into three groups: G1: perivascular dermatitis (18/28, 64%); G2: Drug reaction (7/28, 25%); and G3: Generalized exanthema and chilblain (3/28, 11%). The virus was not detected in the skin, by PCR and by immunohistochemical analysis, and the interleukin expression in the skin were undetectable results. Vascular cell adhesion molecule 1 (VCAM1), E-selectine, and IT Galpha 5 were unspecific. G1 exhibited the least inflammation, G2 the most in-flammatory, and G3 had previous inflammation. Discussion: Our data suggest that generalized exanthemas during severe SARS-Cov-2 infection exhibit unspecific finding and are similar to other rashes caused by inflammation. Drug reaction should be considered, as they accounted for 25% of the rashes. Further studies including higher number of patients are necessary.

In the first wave of COVID-19, up to 20% of patients had skin lesions with variable characteristics. There is no clear evidence of the involvement of the SARS-CoV-2 virus in all the cases; some of these lesions may be secondary to drug hypersensitivity. To analyze the possible cause of the skin lesions, we performed a complete allergology study on 11 patients. One year after recovery from COVID-19, we performed a lymphocyte transformation test (LTT) and Th1/Th2 cytokine secretion assays of PBMC. We included 5 nonallergic patients treated with the same drugs without lesions. Except for one patient who had an immediate reaction to azithromycin, all patients had a positive LTT to at least one of the drugs tested (azithromycin, clavulanic acid, hydroxychloroquine, lopinavir, and ritonavir). None of the nonallergic patients had a positive LTT. We found mixed Th1/Th2 cytokine secretion (IL-4, IL-5, IL-13, and IFN-γ) in patients with skin lesions corresponding to mixed drug hypersensitivity type IVa and IVb. In all cases, we identified a candidate drug as the culprit for skin lesions during SARS-CoV-2 infection, although only three patients had a positive drug challenge. Therefore, it would be reasonable to recommend avoiding the drug in question in all cases.