New Study: Anaphylaxis Hospitalizations Double Among U.S. Children

The number of U.S. children who were hospitalized due to food-induced anaphylaxis more than doubled between 2000 and 2009, according to a new study, which was published online Aug. 7 by the Journal of Allergy and Clinical Immunology. In addition, the authors report that the “charges and costs of [food-induced anaphylaxis] admissions have increased dramatically over time, adding to an emerging literature on the large economic burden of food allergy in the United States.”

The authors, including Carlos A. Camargo, MD (Harvard Medical School), previous recipient of a FARE research grant, analyzed records for more than 12 million inpatient discharges from the Healthcare Cost and Utilization Project (HCUP) Kids’ Inpatient Database. HCUP is part of a family of healthcare databases sponsored by the federal Agency for Healthcare Research and Quality.

Hospitalizations (admissions) due to food-induced anaphylaxis rose from 1,085 in 2000 to 2,253 in 2009.  Throughout this period, demographics remained consistent: the average age of patients was around eight; in 2000, 56 percent were male, vs. 55 percent in 2009; and there were no significant changes in the make-up of patients’ races or ethnicities. Overall, the highest hospitalization rates were in the Northeast, and the lowest were in the South. Except for children who were two years old or younger, significant increases in hospitalization were seen in all age groups. While the average length of patients’ hospital stay remained stable (from 2.3 days in 2000 to 1.9 days in 2009), the researchers report that “total charges more than tripled over the 10-year period, and total costs (data available 2003-2009) also significantly increased.” They conclude that “this trend highlights the need for further research on the inpatient management of [food-induced anaphylaxis] and how to prevent these hospitalizations.”

New Study: Prevalence of Peanut Allergy is High in Elementary School-Age Children

Over the years, numerous studies have attempted to determine the prevalence of food allergies in U.S. children, based on varying criteria. In a letter to the editor, published online on July 30 in the Journal of Allergy and Clinical Immunology, researchers report the results of a new study funded by the National Institutes of Health, which shows that peanut allergy is “an increasingly prevalent condition” among school-age children in the U.S. Researchers concluded that the prevalence of  clinical peanut allergy among children between the ages of 7 and 10 was 5 percent – higher than previous estimates.

Dr. Supinda Bunyavanich (Icahn School of Medicine at Mount Sinai, New York, NY) and colleagues studied the prevalence of peanut allergy among 616 children between the ages of 7 and 10. These children were participants in Project Viva, a study that has been exploring a wide range of health issues among more than 2,000 women and their children in eastern Massachusetts for more than a decade. The researchers also compared their results to prevalence estimates from previous studies.

In their analysis of the Project Viva group, the researchers determined the prevalence of peanut allergy based on several different sets of criteria:

  • Self-reported peanut allergy (based on mothers’ responses to questions about symptoms and history of reactions): 6 percent
  • Clinical peanut allergy (based on laboratory results): 5.0 percent
  • Peanut allergy based on laboratory results, plus an epinephrine auto-injector prescription: 4.6 percent
  • Peanut allergy based on blood test results that show the highest level of sensitivity to peanut, plus an auto-injector prescription: 2.0 percent

In all cases, the prevalence rates were higher than those reported in previous studies using comparable criteria.

Winter Birth Increases Food Allergy Risk in Inner-city Asthmatic Children

Inner-city asthmatic children who were born in the winter (December, January and February) are more likely to be sensitized to egg, peanut or soy allergens than their counterparts who are born in other seasons, according to a recently published study in the Journal of Allergy and Clinical Immunology.

A multi-center research team, led by J. Andrew Bird, MD (University of Texas Southwestern Medical Center, Dallas) analyzed serum and historical information for 427 inner-city children with asthma. Eighty-two percent of the children were African American. Sixty-four percent were males, ranging in age from five to eight, and most lived in the northern U.S. (predominantly in Boston, Chicago or the Bronx). The researchers looked for a relationship between the children’s season of birth and the likelihood that they were sensitized to milk, egg, peanut, tree nuts, soy, codfish, shrimp or various indoor allergens (cockroach, mold, dust mites). They also analyzed the data to see if there was a relationship between allergen sensitization and the children’s vitamin D status, but did not find one. In addition, the study found no relationship between winter birth and sensitization to indoor allergens.

Previous studies have found an association between food allergies and season of birth, but they have focused primarily on Caucasian children. This is the first study to establish a connection between winter birth and sensitization to egg, peanut and soy in a predominantly black, inner-city population. The authors suggest more research be done to determine whether other factors, including winter viruses, geographic location and indoor allergen exposure, may affect food allergen sensitization during the winter.

Researchers Discover Cause of Eosinophilic Esophagitis

Researchers report that they have discovered the cause of eosinophilic eophagitis (EoE), a hard-to-treat food allergy. In EoE, large numbers of white blood cells, known as eosinophils, accumulate in the lining of the esophagus (the tube that connects the mouth to the stomach), causing chronic inflammation. Led by a team at Cincinnati Children’s Hospital, investigators have found a new genetic and molecular pathway in the esophagus. This discovery, reported online today in Nature Genetics, opens the door to new therapies for EoE, which has been diagnosed in a growing number of children and adults over the past decade.

The study found that EoE is triggered by the interplay between epithelial cells, which help form the lining of the esophagus, and a gene called CAPN14. When the epithelial cells are exposed to an immune hormone called interleukin 13 (IL-13), which is known to play a role in EoE, they cause a dramatic increase in CAPN14. CAPN14 encodes an enzyme called calpain14, which is also part of the disease process. Because drugs can target calpain 14 and modify its activity, the study opens up new therapeutic strategies for researchers to explore.

drmarkrothenberg125x156“In a nutshell, we have used cutting-edge genomic analysis of patient DNA, as well as gene and protein analysis, to explain why people develop EoE,” says Marc E. Rothenberg, MD, senior investigator on the study. “This is a major breakthrough for this condition … Our results are immediately applicable to EoE and have broad implications for understanding eosinophilic disorders as well as allergies in general.” The study was funded, in part, by the National Institutes of Health (NIH), with additional support from other organizations, including FARE.

Study: People with Eczema Should Avoid Food-Based Skin Products

If you have a skin inflammation such as eczema, using skin cream that contains food ingredients could lead to an allergic reaction, according to a letter to the editor published in the Journal of Allergy and Clinical Immunology: In Practice.

Australian researchers report on the case of a 55-year-old woman who had a life-threatening reaction after eating two mouthfuls of a salad containing goat cheese. Although the woman suffered from eczema and seasonal asthma throughout her life, she had no history of reactions to food. But after conducting tests to track down the problem ingredient, doctors found that she was allergic to goat’s milk.

Further investigation revealed that the woman frequently used a moisturizer containing goat’s milk to soothe her eczema, although she stopped using it when her condition worsened. Rubbing the cream into inflamed skin, however, presumably sensitized her. When she ingested goat cheese, it triggered a reaction that escalated within minutes, requiring emergency treatment with epinephrine.

The researchers believe that this is the first direct evidence that humans can become sensitized to a food allergen by exposure through the skin. However, previous studies suggest that people with eczema have developed food allergies after using soaps and oils that contain wheat, oat, peanut and goat’s milk. The authors advise eczema patients to avoid skin care products and cosmetics that contain food ingredients.

Food Allergens in Medications

A new clinical review provides useful information about the potential presence of food allergens in prescription medications. Although some medications and vaccines do contain substances derived from foods, researchers found that most medications do not contain enough of a food protein to cause an allergic reaction.

In the article published in the June 2014 issue of the Journal of Allergy and Clinical Immunology, Dr. John M. Kelso (Scripps Clinic, San Diego, CA) explains that all medications contain excipients, substances that are added to the active ingredient of a drug during the manufacturing process. Examples include flavoring agents, preservatives and binding materials. The article offers a thorough review of medications that contain food-derived excipients and discusses whether each is safe for patients with food allergies. For example, the MMR (measles-mumps-rubella) vaccine contains negligible or no egg protein and can be given to anyone with egg allergy. The typically available influenza vaccine contains trace amounts of egg protein, but authoritative professional associations have issued statements recommending vaccination for those with egg allergy and declaring that it may be administered safely with some precautions.  On the other hand, some vaccines, including MMR, may trigger a reaction in people who are allergic to gelatin. Fortunately, this allergy is not common. People with fish allergy may safely consume fish oil, since it does not contain fish protein.

Dr. Kelso further notes that if a person does have a reaction to a medication, the drug may be from a specific lot that was accidentally contaminated with food protein. “In most circumstances these medications should not be routinely withheld from patients who have particular food allergies because most will tolerate the medications uneventfully,” he writes. “However, if a particular patient has had an allergic reaction to the medication… allergy to the food component should be investigated.”

Exploring the Natural History of Egg Allergy

eggEgg allergy is among the most common food allergies in children. One of the most comprehensive examinations of the natural history of egg allergy to date was published in the February 2014 issue of the Journal of Allergy and Clinical Immunology. Researchers from the Consortium of Food Allergy Research (CoFAR) set out to describe the natural course of egg allergy and to identify early predictors of the disease. Over a period of 74 months, they tracked the allergy in 213 children who were between 15 months and 3 years old at the beginning of the study.

By age six, approximately half of these children were able to tolerate egg. Compared to children who were not able to tolerate egg, these children had lower levels of egg-specific IgE, the antibody associated with food allergy. Based on these and other observations, the authors of this study—many of whom serve as advisors to FARE—have developed a calculator that may predict the history of egg allergy in individual patients. Further studies are needed to validate the accuracy of this calculator. The study authors estimate that approximately 50 percent of children with egg allergy will become tolerant to egg by the age of 6. The National Institutes of Health (NIH) was the principal funder of this study.

This article was originally published in the Spring 2014 issue of FARE’s Food Allergy News. Read more of the newsletter here.