Adverse Events and Vaccination: Extensive Local Reaction after Anatoxin Vaccine—A Case Report

Post-vaccine adverse reactions are unwanted medical events that concern both the public and healthcare professionals. The objective of this paper is to present a detailed analysis of the case of an extensive local adverse reaction after the administration of a vaccine dose containing diphtheria–tetanus anatoxins. A good knowledge of post-vaccine side effects allows for complete and correct diagnosis, as well as appropriate individualized recommendations. Such an approach contributes to restoring public confidence in vaccines and vaccinations. The patient was a 6-year-old boy, with a history of asthma under chronic treatment with corticosteroids. He developed extensive local inflammatory lesions accompanied by functional disorders of the left arm, which began six hours after the administration of the fifth dose of the diphtheria–tetanus–pertussis–poliomyelitis vaccine. The lesions, which extended to the forearm, were locally treated with antiseptics and systemically treated with hydrocortisone hemisuccinate. They completely remitted within 14 days. Laboratory investigations revealed neutrophilia (6,870 neutrophils/µL), which could be related to the long-term treatment with steroids. The investigation needed the plasma concentration of diphtheria and tetanus anatoxins antibodies and the pro-inflammatory cytokines to be complete.