Incidence Of Anaphylaxis Higher Than Previously Reported
A new study from the Mayo Clinic published in the December issue of the Journal of Allergy and Clinical Immunology (JACI) indicates a higher incidence of anaphylactic reactions than previously reported.
In the study, entitled "The etiology and incidence of anaphylaxis in Rochester, Minnesota," Wyatt W. Decker, M.D., chief of emergency medical departments at the Mayo Clinic in Rochester, Minn., and his team report that there were 50 emergency room visits per 100,000 population per year caused by anaphylaxis. In addition, the researchers found that the incidence rate of anaphylaxis increased significantly from 1990 to 2000, echoing results reported in studies conducted in the U.K. and Australia.
One third of the anaphylaxis cases Dr. Decker and his team identified were caused by a food allergy reaction. These findings give added urgency to the need for improved treatment and education to help people with food allergies avoid this life-threatening condition.
"We don't think the incidence of anaphylaxis has doubled, but through the Rochester Epidemiology Project we were able to much more meticulously identify cases which in other studies might not have been identified," says Dr. Decker. "So this study gives us a more accurate picture of the magnitude of the problem. Still, we did see about a 10 percent increase in cases of anaphylaxis over the 10-year period of the study."
Dr. Decker and his team identified all cases of anaphylaxis between 1990 and 2000 in Olmsted County, Minn. The researchers also gathered information on age, gender, race, cause of anaphylaxis, presence of other allergic diseases, and symptoms.
* Children ages 0 to 19 are at the highest risk for anaphylaxis.
* Insect stings accounted for 19 percent and medications for 14 percent of cases. The rest were due to some other cause (e.g., cats, latex, unknown).
* None of the medical records involved a fatal reaction.
The previous estimate of 30,000 emergency room visits per year as a result of food allergies was based on a 1999 study, "Epidemiology of anaphylaxis in Olmsted County," by Michael W. Yocum, M.D., and his colleagues. Yocum's and Decker's studies used the same definition of anaphylaxis and data from the same source. Based on the new study, it's estimated that food allergies cause 50,000 emergency room visits per year, with overall anaphylaxis cases approaching 150,000 annually.
"Research findings continue to indicate that severe food allergy reactions are a major public health concern. This study shows anaphylaxis affects significantly more people, many of whom are children, than previously reported," said Anne Munoz-Furlong, Founder and CEO of the Food Allergy & Anaphylaxis Network (FAAN). "There is no treatment or cure for food allergies. Avoidance is the only way to prevent a reaction. As reactions continue to increase, we need to continue refining guidelines and protocols to improve diagnosis and treatment for the more than 12 million Americans who have food allergies."
The researchers in this FAAN-funded study used data from the Rochester Epidemiology Project (REP), a unique medical records linkage system funded by the National Institutes of Health. Since 1966, the REP has linked and indexed nearly all the medical records of Olmsted County residents, providing a complete picture of health conditions among this population. Because these records are so complete and detailed, researchers have used them to estimate national figures for many conditions besides anaphylaxis, such as cancer and asthma. Studies have shown that these estimates are accurate for white Americans as a whole.