Severe immune haemolysis after standard doses of Penicillin

Summary Penicillin causes immune haemolytic anaemia by the 'drug-adsorption' mechanism and typically occurs after prolonged exposure to large doses of the drug. Withdrawal of the drug is associated with improved red cell survival and gradual cessation of haemolysis. Although this complication is uncommon, it can be potentially serious. An unusual case is described herein. The patient was exposed to a short course (9 days) of standard dose penicillin but suffered acute severe haemolysis about 1 week after cessation of therapy. A high titre anti-penicillin antibody (1 : 512) not cross-reacting with cephalosporins, was demonstrated. The delay in the development of immune haemolysis vis-à-vis penicillin therapy may be due to the patient being immunologically naive to the drug. Penicillin may persist for weeks in circulation, coating red cells and providing continued antigenic stimulation for the development of anti-penicillin antibody.