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

Area of Science:

• Immunology
• Dermatology
• Vaccinology

Background:

• The widespread use of SARS-CoV-2 vaccines has prompted investigation into their safety profiles, including allergic reactions.
• While anaphylaxis is rare, benign cutaneous reactions are frequently observed post-vaccination.

Observation:

• Delayed benign cutaneous hypersensitivity reactions typically manifest as localized erythema, pruritus, and rash at the injection site.
• Rarely, these reactions can present at sites distant from vaccine administration.

Findings:

• This case report describes a unique instance of delayed benign cutaneous hypersensitivity in the lower extremity following an upper extremity mRNA SARS-CoV-2 vaccine administration.
• The reaction presented with rash and atopy, distinct from typical localized responses.

Implications:

• This case highlights the variability in presentation of vaccine-induced hypersensitivity reactions.
• Understanding and recognizing these atypical presentations is crucial for effective clinical management of patients experiencing post-vaccination cutaneous reactions.