Reproducibility of Symptom Sequences Across Episodes of Recurrent Anaphylaxis.

Background: Anaphylactic reactions may present with varying levels of severity, ranging from mild multisystem involvement to severe, and sometimes fatal, anaphylaxis. The severity of anaphylaxis is variable from one reaction to the next within the same individuals.

Objective: To compare the temporal sequence of symptoms within individuals and between individuals across multiple anaphylactic reactions.

Methods: Patients were evaluated for recurrent anaphylaxis in a tertiary care allergy clinic between 2012 and 2018. At each visit, patients were asked to record the temporal sequence in which symptoms of anaphylaxis appeared. These data were recorded at each visit and retrieved through retrospective chart review. Patients with a history of ≥2 anaphylactic reactions were included; those with anaphylaxis due to multiple allergens were excluded. The Fleiss Kappa method was used to assess reproducibility of the order of appearance of specific symptoms during anaphylaxis within individual patients and between individuals with similar triggers.

Results: The mean patient age was 35.6 years (standard deviation = 13.9; range: 1-68 years); 113 of 149 (76%) patients were female. The mean Fleiss Kappa reproducibility score within individuals was 0.94, 5th percentile was 0.53, and 95th percentile was 1.0. The mean Kappa score between individuals was -0.03 (range, -0.14 to 0.05). Among the 16 of 149 patients who recorded reactions of varying severity grades, the mean within-patient Kappa score was 0.96.

Conclusion: Individual patients experience reproducibly stereotypic anaphylactic reactions over time, which are unique to a given patient, irrespective of the cause of anaphylaxis, including foods, medications, mast cell disorders, and idiopathic anaphylaxis. In contrast, symptom sequences during anaphylaxis are not reproducible between individuals.