[Anaphylaxis: clinical aspects, etiology and course in 118 patients]

Systemic anaphylaxis is a potentially life-threatening clinical syndrome resulting from the release of biologically active substances such as histamine or prostaglandins upon a target organ. The aims of our study were to analyze clinical data, causative agents and follow-up in subjects with severe anaphylaxis. Of 5689 subjects who were referred from May 1994 through October 1996 to the allergy-immunology out-patient clinic of the University of Berne, 118 (2.1%; 68 females and 50 males; mean age 41 years) had experienced severe systemic anaphylaxis with hypotension, loss of consciousness or shock. 104 individuals (88.1%) showed accompanying dermal symptoms, 85 (72.0%) respiratory and 52 (44.1%) gastrointestinal signs. Causative agents were identified in 93.2% of these attacks; they included drugs (33.9%), insect stings (23.7%), foods (18.6%), exercise (8.5%), latex (7.6%), and immunotherapy (0.9%) with pollen extracts. A suspected cause could not be determined in 8 subjects. Atopy was present in 64 individuals (54%). Prior to the index anaphylaxis, 21 of 110 subjects (19.1%) with an identified cause had experienced more than one episode of anaphylaxis. Follow-up survey showed that 29 of these 110 individuals (26.4%) were accidentally reexposed to the causative agents. 19 of 24 patients (79.2%) used their emergency kits, while 5 were not equipped with. Only one severe systemic reaction occurred in a subject who intentionally reexposed himself to the identified cause of anaphylaxis. Besides cardiovascular symptoms, systemic anaphylaxis most often involves the skin and respiratory tract. Since prevention of anaphylaxis focuses upon avoidance of precipitating factors, all individuals with anaphylaxis should be referred to an allergologist for identification of the causative agents. The cause of anaphylaxis could be determined in the majority of patients with anaphylaxis. However, unexpected exposures are frequent. Thus, all patients who have had one or more episodes of anaphylaxis should carry an emergency kit for self-administration, and should be instructed in its use.