BIPHASIC SYSTEMIC-ANAPHYLAXIS - AN INPATIENT AND OUTPATIENT STUDY

We attempted to ascertain the incidence of systemic biphasic anaphylactic reactions in both outpatients and inpatients. Madigan Army Medical Center is a large teaching facility. The Allergy Clinic staff sees approximately 20,000 patients per year, and an average of 27,000 allergy immunotherapy injections are administered each year. During the years 1988 to 1991 we collected data from a total of 35 patients who had experienced during the 30-minute waiting period in the clinic, symptoms and signs consistent with anaphylaxis. A total of 44 anaphylactic reactions were noted, with only two (5%) involving a biphasic systemic pattern. All patients were observed and treated within the clinic until symptoms and signs had resolved. None of the patients were treated with or were presently using glucocorticosteroids during the time of their reactions. Of the reactions noted 25 (57%) involved only cutaneous manifestations of anaphylaxis, three (7%) involved the laryngeal/upper airway area, eight (18%) involved bronchospasm alone, three (7%) involved the rhinoconjunctivae, and five (11%) involved more than one site or type. None of the patients experienced any symptoms or signs of cardiovascular compromise or collapse after allergy extract injections. During the years 1986 to 1992 a total of 59 patients were admitted to the medical ward or intensive care unit with the diagnosis of systemic anaphylaxis. Of 59 patients, four (7%) experienced a recurrent (biphasic) anaphylactic reaction without reexposure to the initial inciting agent. The remaining 55 patients (93%) did not experience any further systemic anaphylaxis after initial hospital admission and treatment. Two of the patients with biphasic anaphylaxis were first seen with hypotension and generalized urticaria. Of the remaining two patients, one had lip and tongue angioedema, and the other had urticaria only. The biphasic reaction involved antibiotics in two cases and food (shrimp) in the remaining two cases. Forty-two male patients and 17 female patients were included in the study. The age range of male patients was 6 months to 77 years and that of the female patients was 10 to 81 years. There were no deaths in this study. Of the causes for anaphylactic episodes 20 (34%) were drug- or medication-related 12 (20%) were idiopathic, 13 (22%) were related to food, six (10%) were secondary to exercise, two (3%) were related to vaccine administration and three (3%) were secondary to Hymenoptera stings. The four remaining episodes were secondary to contrast dye administration, allergen skin test extract administration, horse serum administration, and allergen extract injection. We conclude that the incidence of biphasic anaphylactic events is lower than that reported in previously published studies.