Acantholytic Dyskeratosis Post-COVID Vaccination.

Acantholytic dyskeratosis mimicking Grover disease as a cutaneous manifestation of a side effect to the Moderna (mRNA-1273) COVID vaccine is rare with only one documented case in the literature to date. Herein, we present a case of an eruptive, erythematous, vesiculopapular rash developing in a patient after the Moderna vaccine. Histopathology of a representative biopsy [x2, done 8 weeks apart] of the rash revealed similar histopathologic findings of patchy suprabasal acantholysis with dyskeratotic keratinocytes and an underlying inflammatory infiltrate of lymphocytes and neutrophils. Direct immunofluorescence was negative. In contrast to the only case previously reported in the literature, a confounding feature in our case, was that patient had a medical history significant for Grover disease, which had been successfully treated with complete resolution and seemed to be in remission. Given the temporal relationship of the onset of the rash to vaccine administration, the changes were likely vaccine-related with the caveat that, in light of the medical history, the differential diagnosis includes reactivation of Grover disease by the vaccine as a trigger factor.