Abstract

With the development of two US Food and Drug Administration (FDA)-approved mRNA vaccines against the SARS-CoV-2 virus, reports of delayed cutaneous hypersensitivity reactions are beginning to emerge. The objective of this retrospective case series is to describe the histopathological features of cutaneous eruptions biopsied after receiving either the Pfizer-BioNTech or Moderna mRNA vaccine against the SARS-CoV-2 virus. Patients were seen by their primary dermatologist in either a private practice or academic setting. Skin biopsies were submitted to a dermatopathology laboratory at a single urban academic center for microscopic examination and histopathologic diagnosis. In total, ten patients (six women; age range: 29 to 95 yo) underwent a skin biopsy for a cutaneous eruption that began after receiving an mRNA vaccine against the SARS-CoV-2 virus. Five patients received the Pfizer vaccine, and five patients received the Moderna vaccine. Two patients experienced injection site reactions that demonstrated a hypersensitivity reaction pattern. Generalized eczematous or morbilliform eruptions developed in four patients. In one patient with underlying atopic dermatitis, vaccination triggered a flare of disease. Finally, three patients experienced other immune-mediated reactions, ranging from urticarial vasculitis to leukocytoclastic vasculitis to bullous pemphigoid. We conclude that dermatologists should be aware of potential cutaneous adverse reactions to mRNA-based COVID-19 vaccines, which may include localized hypersensitivity reactions, generalized eruptions, flare of pre-existing dermatological conditions, and other immune-mediated dermatoses. Histopathological examination may be necessary for immune-mediated cutaneous presentations.

Financial Disclosure: No current or relevant financial relationships exist.