Delayed allergic skin reactions to vaccines

Area of Science:

• Immunology
• Dermatology
• Vaccinology

Background:

• Vaccination advancements for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have highlighted immediate and delayed hypersensitivity reactions.
• Allergists and dermatologists play a key role in managing these vaccine-related hypersensitivity responses.

Purpose of the Study:

• To review delayed hypersensitivity reactions to vaccines.
• To identify potential causative agents and provide diagnostic and management strategies, including patch testing for future vaccine administration.

Main Methods:

• Literature review of published reviews and case reports in PubMed.
• Inclusion of vaccine data from the Centers for Disease Control and Prevention (CDC) website.
• Selection of relevant case reports and reviews focusing on delayed vaccine reactions.

Main Results:

• Delayed hypersensitivity reactions often manifest as cutaneous symptoms, ranging from localized nodules to systemic rashes, with onset varying from days to weeks.
• Identified excipients implicated in delayed reactions include thimerosal, formaldehyde, aluminum, antibiotics, and gelatin.
• Antihistamines, topical, or systemic corticosteroids effectively manage symptoms; reactions are typically not contraindications for future vaccination.

Conclusions:

• Delayed-type hypersensitivity reactions to vaccines are relatively common.
• Patch testing can confirm specific agents like antibiotics, formaldehyde, thimerosal, and aluminum when necessary.
• Most delayed cutaneous reactions do not preclude subsequent vaccine administration.