Epidemiology of Anaphylaxis: Contributions From the Last 10 Years.

Knowledge of the epidemiology of anaphylaxis has improved during the last 10 years thanks to the increased number of publications with improved methodological robustness. Consequently, we better understand the distribution and frequency of anaphylaxis and the characteristics of fatal anaphylaxis. We now know that anaphylaxis is more frequent than previously thought (up to 50-103 cases per 100 000 person-years), although the distribution differs with the age group (up to 3 times in patients aged 0-4 years), cause (food-induced anaphylaxis is more frequent in young people, drug-induced and Hymenoptera anaphylaxis in older patients), and geographical area (more prevalent in areas with less sunlight). A controversial and unresolved issue is whether this high incidence of anaphylaxis is a real increase or merely the result of better identification of anaphylaxis by the attending physician. Recurrence of anaphylaxis has been recorded in one-third of cases, although it is the least studied area of the epidemiology of anaphylaxis. Fatal anaphylaxis, on the other hand, has been widely studied. We know that death from anaphylaxis is a rare and extraordinary event (0.12 to 1.06 deaths per million person-years) and more likely in older individuals in the case of drug and Hymenoptera anaphylaxis. Studies conducted during the last 10 years are highly powered since they include large numbers of patients (national records of hospitalized patients) over long time periods (10-20 years) or have been conducted with representative samples of the general population.