Kate Johnson

March 16, 2012

March 16, 2012 (Orlando, Florida) — Patients with asthma who fail oral food challenges (OFC) are less likely to have respiratory symptoms than their nonasthmatic peers, according to a study presented here at the American Academy of Allergy, Asthma and Immunology 2012 Annual Meeting.

The findings should encourage physicians who avoid or delay testing asthmatic patients for fear of exacerbating their symptoms, said Carrie Lee, NP, RN, from the Medical College of Wisconsin in Milwaukee.

"It's safe," she told Medscape Medical News during a featured poster session. "If you have an oral food challenge protocol that incorporates all the safety measures, with cutoffs for Ig [immunoglobulin]E levels and wheal size, it's a safe thing for patients with asthma to go through."

Lee and colleagues conducted a retrospective chart review of 105 patients (57% male) from 9 months to 74 years of age with a history of food allergy, defined as a history of symptoms on exposure and a positive skin prick test, and/or elevated serum-specific IgE.

One third of the subjects (n = 29) had asthma; the remaining (n = 76) did not.

All patients underwent OFC to a variety of foods, including egg, milk, soy, wheat, tree nuts, peanuts, shellfish, finned fish, egg in product, milk in product, and sesame and sunflower seed butter.

The OFC protocol was identical for asthmatic and nonasthmatic subjects, except asthmatic subjects also underwent spirometry on the day of the challenge.

All patients had to be "under a specific wheal size and IgE level for the food, or had to have had a recent injection for the food without a reaction," said Lee.

Only 2 of the 29 asthma subjects (7%) failed the OFC, compared with 17 of the 76 nonasthmatic subjects (22%).

"We were expecting to see respiratory symptoms in the asthma patients who failed the challenge. In fact, we found that they did not exhibit respiratory symptoms; they had other [symptoms]. In those who didn't have a history of asthma, some had wheeze and cough," she said.

Symptoms in the 2 asthmatic subjects who failed the OFC (one was allergic to peanut and the other to sesame seed butter) included tongue pruritus, emesis, and urticaria.

In addition to wheeze and cough, the nonasthmatic subjects experienced erythema, emesis, urticaria, pruritus, rhinorrhea, throat complaints, and food refusal.

Although none of the subjects required epinephrine, the asthmatic patients were treated with oral cetirizine, and the nonasthmatic patients were treated with oral cetirizine (n = 13), oral prednisolone (n = 3), or inhaled albuterol (n = 2).

Donna Mitchell, RN, MSN, CPNP, a nurse practitioner specializing in pediatric allergy at the Children's Hospital of Richmond at Virginia Commonwealth University, said the findings are similar to her experience and might simply reflect a well-controlled asthmatic population.

"If your asthma wasn't controlled and you had a food challenge reaction, you'd be more likely to have a respiratory component," she told Medscape Medical News.

Commenting on the findings, David Elkayam, MD, from the Bellingham Asthma, Allergy, and Immunology Clinic in Washington, warned that "the data are interesting but premature and observational, and could perhaps embolden [patients and/or parents] to try at-home challenges even in situations of potential high risk."

Although most deaths from food allergies are known to occur in concomitantly food allergic and asthmatic individuals, food allergy is not necessarily the cause of the asthma, and therefore food challenge would not necessarily exacerbate asthmatic symptoms, he explained.

"Elimination and provocation challenge with foods infrequently induces asthma in monitored challenges, and has only rarely been shown to cause asthma alone without also causing gastrointestinal and skin symptoms (hives)," he said.

"I find it interesting that there were several more cough/wheeze events in the nonasthmatic population — How often do you actually get patients to wheeze if you don't have reactive airway disease and asthma? — as well as more episodes of urticaria."

None of the speakers have disclosed no relevant financial relationships.

American Academy of Allergy, Asthma and Immunology (AAAAI) 2012 Annual Meeting: Abstract 552. Presented March 4, 2012.


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