Allergic Reaction to Vaccination

Redness and swelling after a pneumococcal vaccine the day before in a 66-year-old woman. This allergic reaction looks like bacterial cellulitis. It resolved with oral diphenhydramine. (Courtesy of Richard P. Usatine, MD.)
Read more about allergic reactions to vaccinations in context:
Color Atlas of Family Medicine: Chapter 120. Cellulitis
Read more about allergic reactions to vaccinations:
Harrison’s Principles of Internal Medicine, 20e: Chapter 118. Immunization Principles and Vaccine Use
CURRENT Diagnosis and Treatment Family Medicine: Chapter 7. Routine Childhood Vaccines