Localized Delayed T-cell Mediated Hypersensitivity After mRNA SARS-CoV-2 Vaccination

Since the emergency authorization of SARS-CoV-2 vaccines, the medical literature has been investigating the management of allergic reactions to the vaccines. Anaphylaxis has been reported among a minority of vaccinated individuals, and many trials monitoring the safety profile of the vaccines have identified cases of benign cutaneous reactions. Typical features of delayed benign cutaneous hypersensitivity reactions include localized erythema, pruritus, and rash. However, reports have described rare cases of rash and atopy at sites apart from the injection site following vaccine delivery. We will discuss a unique case of delayed benign cutaneous hypersensitivity presenting in the lower extremity after an upper-extremity administration of an mRNA SARS-CoV-2. Additionally, we describe management strategies to guide clinicians who encounter similar vaccine-induced hypersensitivity reactions.