Histopathologic Features of Chilblainlike Lesions Developing in the Setting of the Coronavirus Disease 2019 (COVID-19) Pandemic.

CONTEXT.—: During the coronavirus disease 2019 pandemic, several studies have described a distinctive cutaneous manifestation with a clinical picture resembling chilblains or chilblain lupus in young patients.

OBJECTIVE.—: To report the histopathologic description of a series of chilblainlike lesions appearing in the context of the severe acute respiratory syndrome coronavirus 2 epidemic.

DESIGN.—: The study included 13 patients with cutaneous acral lesions resembling chilblains occurring in the setting of suspected severe acute respiratory syndrome coronavirus 2 infection with available skin biopsy.

RESULTS.—: Two main histopathologic patterns were observed: a chilblainlike histopathologic pattern (10 of 13 cases; 77%) and a thrombotic vasculopathy pattern (3 of 13 cases; 23%). The chilblainlike histopathologic pattern featured a superficial and deep perivascular infiltrate of lymphocytes of varying intensity. This infiltrate was sometimes peri-eccrine and alterations of eccrine glands were present in most cases. Vacuolar alteration of the basal layer of the epidermis was found in a majority of patients. Lichenoid interface dermatitis was rarely present. The thrombotic vasculopathy pattern featured an absent or mild inflammatory infiltrate, multiple intraluminal fibrin thrombi, and ischemic epidermal necrosis. In both patterns, no true vasculitis was observed. No patient tested positive for severe acute respiratory syndrome coronavirus 2 by polymerase chain reaction, possibly because these lesions may represent late cutaneous manifestations of the disease or are associated with an early effective immune response.

CONCLUSIONS.—: The relationship of chilblainlike lesions to severe acute respiratory syndrome coronavirus 2 requires further investigations. Histopathologic features mimic chilblains, chilblain lupus, and, less frequently, a thrombotic vasculopathy. Response to viral infection might trigger diverse mechanisms leading to the 2 histopathologic patterns described.