Oral food challenges needed for accurate food allergy diagnoses among military personnel

LOUISVILLE, Ky. — Most patients at a military medical center with a suspected food allergy passed their oral food challenges, according to a presentation at the American College of Allergy, Asthma & Immunology Annual Scientific Meeting.

OFCs are particularly necessary among military personnel because food allergies can impact readiness, Maj. Mechelle Miller, MD, of the allergy, immunology and immunizations service, department of medicine, at Walter Reed National Military Medical Center (WRNMMC), said during her presentation.

“Food allergy can affect anywhere between 1 in 13 and 1 in 25 persons who may desire to join military service,” Miller said. “This poses an unforeseen constraint in the country’s ability to recruit and maintain a medically ready and deployable fighting force due to limited food options and medical support in austere environments.”

Food allergies also could impact an individual’s ability to enlist in the military or enroll in a military academy or have a negative impact on career options such as joining special forces, becoming a pilot or even remaining in the military, Miller added.

Family members with food allergies can present obstacles as well, as their need for care may prevent personnel from accepting career-advancing assignments too, Miller continued.

“More information about oral food challenge outcomes in the military and beneficiary population can clarify who should and should not serve,” Miller said.

Overall outcomes

The researchers examined the results of 1,112 outpatient OFCs conducted for 652 patients with IgE-mediated food allergies in the WRNMMC allergy and immunology department between June 2014 and September 2021.

According to the researchers, 910 (81.8%) of the tests were negative, including 615 (82%) pediatric and 294 (81.4%) adult OFCs. Almond (94.4%), shrimp (94.2%), crab (91.9%) and egg (88.9%) had the highest pass rates, and cashew (62%), walnut (63.5%), pistachio (69.7%) and pecan (71.2%) had the lowest.

Miller particularly noted that during the walnut OFCs, the pediatric subgroup had a 74.4% pass rate, whereas the adult subgroup had a 40% pass rate (P = .008).

OFC outcomes appeared significantly related to specific IgE (P < .001), skin prick test wheal size (P < .001) and history of a prior failed challenge (P = .042).

There was an association between higher levels of Ara h 2 and a greater number of failed peanut challenges as well (P = .045), Miller said, but these tests were only implemented in 2020 and the number of challenges was small.

Pediatric data

Considering the lack of data in the literature and the future impact on military readiness, the researchers took a closer look at the pediatric data. The pediatric population included slightly more boys and presented with more atopic dermatitis, compared with rhinitis and asthma, Miller said, with many patients having multiple food allergies.

Researchers found that atopic dermatitis (P = .015), number of food allergies (P = .049) and IgE (P = .003) were significantly related to OFC failure rates.

The most common OFCs in the pediatric group included tree nut (34.29%), peanut (18.12%) and miscellaneous (10.95%), with the highest pass rates occurring for shellfish (95.65%), miscellaneous (91.76%), wheat (91.67%), egg (88.46%), baked egg (85.11%), soy (81.82%), milk (81.08%) and tree nut (79.47%). Sesame had the lowest pass rate (44.44%), although Miller noted that this subgroup had a smaller number of challenges.

Further, lower sIgE totals were associated with passed OFCs, Miller said. For example, average sIgEs were lower among patients who passed vs. failed the baked milk (12.73 kU/L vs. 29.75 kU/L) peanut (0.68 kU/L vs. 5.5 kU/L), pistachio (0.38 kU/L vs. 5.63 kU/L) and cashew (0.37 kU/L vs. 2.5 kU/L) OFCs.

“Specific IgE was a reliable marker for assessing the pretest probability of passing the challenge,” Miller said.

The study highlighted the importance of food allergy in military preparedness and career paths as well as the role of OFCs in accurate diagnosis, Miller concluded, but the work is not finished yet.

“More studies are needed on OFCs to assess food allergy’s impact on the military,” she said.