Successful desensitization of a case with desferrioxamine hypersensitivity

Thalassaemia major is a severe chronic hemolytic disease, resulted with iron overload mainly due to regular blood transfusions. Iron overload may lead to serious organ toxicity and even fatal complications, if no iron excretion is achieved by a chelating agent. First introduced in 1976 as s.c. treatment for thalassaemia major, desferrioxamine (DFO) has substantially improved the life expectancy in the disease. While DFO can cause local allergic reactions including redness, itching, pain and lumps, on rare occasion anaphylactic reactions can occur. The mechanism of anaphylaxis like reactions is not well understood. In this case report, we presented a 10 years-old girl with thalassaemia major who had to stop DFO therapy after appearing of systemic allergic reactions with hypotension, tachycardia, pruritus and urticaria against this drug. Serum IgE level was normal, specific IgE and skin prick tests were negative. Intradermal test was resulted with positive reaction to DFO. The patient was hospitalized and desensitization protocol was initiated with rapid s.c. infusions per 15 min. The protocol was stopped at the 17th cycle because of local reaction reappeared. After that, DFO was further diluted and was restarted with lower dosage and longer infusion period. Then, DFO dosage was increased and the dilutions and infusion times were decreased gradually. By this desensitization programme, the patient would continue to use DFO chelation safely for 10 months.