Adverse local reactions to vaccines containing diphtheria and tetanus toxoids and pertussis antigen (DTP) are common, but generally benign. Most often, these reactions are manifested by erythema, induration, and tenderness occurring at the injection site 12 to 24 hours following immunization.1-3 Less frequently, abscess formation may complicate intramuscular injections and these may be staphylococcal, clostridial, or sterile in etiology.4 Tetanus toxoid has been associated with a reaction incidence of 3% to 13%,5,6 and adverse reactions appear to be related to the number of prior immunizations and the height of preexisting antibody responses.3,6 However, recurrent abscess formation associated with hypersensitivity to one or more of the components of the DTP vaccine has not been reported previously.