Recurrent injection site reactions to vaccines: Two clinical patterns of presentation.

After administration of injectable vaccines, skin manifestations are common and they usually disappear in a few hours or days. We describe a case series of recurrent injection site reactions in 8 children undergoing vaccines of the regional immunization schedule, which required specialized evaluation and advice for subsequent vaccinations. Two clinical patterns of reactions were observed. Four children manifested recurrent wheal and erythema with pruritus at vaccine injection site for up to 7 months; the remaining children showed an itching plaque or nodule at injection site, that lasted several months after vaccination with exacerbations of pruritus and erythema. Hypersensitivity to aluminium salts was demonstrated in the second group. The flare-up manifestations, related to Meningococcal B vaccine in 5 reactions, were triggered by concurrent viral infections in two patients. Communication of risks and diagnostic testing, when appropriate, resulted important to reassure parents of children and favour adequate completion of vaccination.