Histopathology and immunophenotyping of late onset cutaneous manifestations of COVID-19 in elderly patients: Three case reports

ACKGROUND Several cutaneous manifestations such as urticarial rash, erythematous patches and chilblain-like lesions have been described in young adults with coronavirus disease 2019 (COVID-19) and are present in up to 20% patients, but few reports exist describing histopathological and immunophenotypic characteristics of dermatological lesions in older patients. Our aim was to characterize skin lesions in elderly patients during late stages of COVID-19 from clinical, histological and immunophenotypic perspectives. CASE SUMMARY Three patients, admitted for COVID-19, and who developed cutaneous manifestations underwent skin biopsies. Immunophenotypic analysis for CD20, CD3, CD4and CD8 was performed on skin biopsies to assess immune cell infiltrates. CD1a was used as a marker of Langerhans cells, and CD31 as a marker of endothelial cells. In the three study patients, cutaneous manifestations were evident in the late-stage of COVID-19 (mean time from the first positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) swab to rash onset was 35 d). Skin biopsies showed a similar pattern of T lymphocyte infiltration in all patients. Indeed, a chronic dermatitis with perivascular lymphocytic infiltrate was observed with predominance of CD3+ T-cell (CD3+). CONCLUSION Our study confirms previous reports. Histological and immunophenotypic patterns in our patients confirm results described in the two previous reported experiences. This pattern is similar to what is found in some lympho-proliferative disorders. Therefore, since these findings are non-specific, SARS-CoV-2 infection should be suspected.