Anaphylaxis caused by mosquito allergy in systemic mastocytosis

In the summer of 1996, a 56-year-old man was bitten on his arm by a mosquito in his garden in Bavaria, Germany. About 15 min later he had diarrhoea, felt nauseous, and lost consciousness. He was bitten again by a mosquito in May, 2001, and August, 2001. Following the bite in August, 2001, the reaction developed rapidly, and he immediately lost consciousness and went into cardiac arrest before the ambulance arrived. Because of delayed resuscitation, he had hypoxic brain damage to the basal ganglia, resulting in spastic tetraplegia. Red-brown maculo papular skin lesions were seen on his upper legs and a skin biopsy showed increased mast cell numbers. In 2006, he was bitten a fourth time by a mosquito. Despite immediate adminis tration of rescue medi cation consisting of epinephrine, H1-antihistamine, and corticosteroid, he again had a severe reaction and cardiac arrest. In 2012, the patient was referred to the depart ment of dermatology and allergy, Charite—Universitatsmedizin Berlin, Germany, for further investigation. On the basis of the history of maculopopular skin lesions and increased mast cell numbers on skin biopsy, we suspected systemic mastocytosis. WHO diagnostic criteria for systemic mastocytosis were confi rmed. Despite having only slightly raised serum tryptase of 11·5 μg/L (normal range