Strategies improve preparation for oral food challenges

Key takeaways:

• A thorough patient history informs the risks and benefits of testing.
• Patients who are ill or actively taking medication should delay testing.
• Staff should be trained and equipped to manage severe reactions.

SAN ANTONIO — Preparation is key to successful oral food challenges, said Maria Crain, APRN, CPNP-PC, AE-C, pediatric nurse practitioner, University of Texas Southwestern Medical Center Food Allergy Center.

“It should be performed in a safe way,” Crain said during her presentation at the 16th Annual Allergy, Asthma & Immunology CME Conference, noting that she and her colleagues perform about 20 open challenges each week.

Risks vs. benefits

Providers first need to assess the risks and benefits of these tests before deciding to perform them, Crain said, and that begins with taking the patient’s history, including the food that caused the index reaction and what the reaction was.

“You want to find out how much of the food they ate, if it was processed, how soon the reaction occurred, what were the symptoms, and, if treatment was given to help, you want to find out when it was,” Crain said.

If the reaction was recent, she added, “you’re not going to do a food challenge anytime soon.” But when previous testing is inconsistent and previous reactions have not been severe, she continued, it may be an indication to go ahead with the challenge.

“You might also consider it when the provider and the family both agree that the risk is low enough that the benefit outweighs risk,” Crain said.

For example, she said, patients with multiple food allergies and restricted diets may see more benefits than risks in testing. She also said that she performs challenges when she is trying to determine if eczema or eosinophilic esophagitis is a contributing factor.

“We do have patients that have EoE and also have IgE,” Crain said. “There may be a patient that is avoiding multiple foods because of their EoE. They want to eat something like fish or shellfish, which is typically benign in that kind of condition.”

OFCs may open their diet up, she said. These challenges also can help providers determine if patients with multiple dietary restrictions are cross-reactive to any foods, such as cashew and pistachio.

“They’ve reacted to cashew. You do the test results. Everything looks low. The family is in agreement. They want to try [pistachio],” Crain said. “I just would do it in a very slow manner and let the family know that there’s still a high risk of reaction.”

OFCs also help determine the impact of food processing, such as baked egg and milk, and improve quality of life when a particular food is culturally important to the family, she said, but informed consent is essential to these decisions.

Informed consent should be verbally documented, or it should be written and signed, she said. Providers also should tell patients and families how long the challenge will take and what symptoms should be expected.

“You want to make sure that they have a good understanding of what this procedure is going to look like and the possibilities of a reaction,” she said.

Need for delay

Yet despite these assessments and discussions, providers may need to delay OFCs even though many families have waited a long time to get them, Crain said, noting 2019 updates to a work group report.

“If a patient is coming for a food challenge with an illness, fever or active respiratory symptoms, they are more likely to have more significant symptoms if you challenge and they react,” Crain said.

This may be difficult, Crain said, adding that she deals with many younger children in daycare who often have runny noses at baseline. She said that it is up to each provider to determine the risk.

“As I’ve been practicing longer, I have been much more conservative about not doing the challenge, because I have done it when they have had mild illness before, and they have had a pretty serious reaction,” she said.

Crain described one recent patient, an infant, who had been waiting for a baked food challenge but was sick the previous week. The infant coughed occasionally and had a runny nose and congestion during the visit but was otherwise happy, Crain said.

“I just told the mom, I think I would probably delay this for a couple weeks, just for safety,” Crain said. “I just let them know that if there was a reaction, it’s going to be difficult for me to determine whether or not this is from the food or just the regular illness.”

Crain said that the mother was understanding once she heard this explanation.

“Sometimes, if patients are waiting for these appointments, you just have to let them know your rationale,” she said. “And most of the time, they understand.”

OFCs also should be delayed for patients who use short-acting beta agonists for cough or wheeze within the previous 48 hours; those with poorly controlled asthma, atopic dermatitis or allergic rhinitis; those with unstable cardiovascular disease; those who are pregnant; those who are on beta blocker therapy; and those who have not discontinued specific medications as recommended by the work group report updates.

“We also don’t want to do challenges on patients that have recently been taking their bronchodilator for asthma or any asthma that’s just not in control,” Crain said.

Many patients have eczema or seasonal allergies as well, she continued, adding that providers will need to determine if these issues are mild or moderate to severe before making any kind of decision.

“We tend to do challenges when it’s not their allergy season, which can be tough,” she said. “Some patients, we still will allow them to take their oral antihistamines up to a day before. That’s controversial.”

The updates to the work group report recommend halting medications a week before OFCs.

“If a patient has actively said they’re on medication, you’re definitely not going to want to do the challenge,” Crain said.

But Crain also said that she and her colleagues make some decisions on a case-by-case basis, as some patients may not be able to stop taking these medications, and they have been waiting for the OFC.

“We might still consider doing the challenge,” Crain said. “Antihistamines are not going to prevent anaphylaxis, so it’s just something, as a provider, you need to decide.”

Similarly, she said she probably would proceed with challenges for patients with mild seasonal allergies who have taken loratadine (Claritin, Bayer) the day before.

“We know that’s probably pretty much out of their system,” she said.

Additional risks

Crain further noted that peanuts, tree nuts, fish, shellfish and milk are most commonly associated with fatal reactions.

“If they have high testing, they have had some reactions in the past, you might want to just make note of that if you’re deciding to do a food challenge,” she said.

Patients with asthma also tend to have reactions that are more severe, she continued, especially if their asthma is not well controlled. Patients who do not get timely epinephrine also are at greater risk, she said.

“Maybe a patient is wheezing in the office, and someone gives them albuterol first. We don’t recommend that,” she said. “We want to give epinephrine first with food allergy, for sure, and then consider giving albuterol later.”

Crain stressed the importance of having emergency medications such as epinephrine, diphenhydramine and ondansetron on hand, with doses already calculated and prepared based on weight, prior to the OFC.

Additionally, when patients do experience anaphylaxis, Crain continued, an upright posture may contribute to cardiovascular compromise.

“We tend to put the patients down with their legs out after we get epinephrine, and we keep them that way for a period of time, until we check vital signs as they’re improving,” Crain said.

Practices need to prepare for these emergencies too, Crain advised.

“You want to be in an area where you have access to either transport, an EMT or a hospital,” she said. “It doesn’t necessarily have to be right there. But you definitely want to have staff that’s experienced in managing a food allergy reaction.”

Crain said that she and her staff conduct mock allergy reactions and know which roles people will assume when reactions happen.

“We know that the medical assistant is going to do vitals and is the point of call if we need an EMT,” she said. “Most of the time, we manage these food allergy reactions in the office. But if they did ever have to go over to the hospital, they are usually stable by the time they get there.”

Crain further advised providers to take baseline vitals before OFCs, including pulse oximetry, blood pressure in older pediatric patients and possible pulmonary function testing when there are asthma concerns.

The physical exam is important as well, she added.

“Focusing on the skin is really important, looking at any nasal symptoms, listening to them, making sure they’re not wheezing and also getting information from the families,” she said.

Providers can ask if patients have been coughing or sneezing, Crain suggested.

“A lot of times I’ll still ask those same questions, and then during the challenge, they start coughing or sneezing,” she said. “The parents say they’ve been doing this all week. Well, they didn’t tell me that beforehand, so it’s good to try to get a detailed history so you know where their baseline is.”

Positive outcomes

Crain said that OFCs are tedious and that they take a long time, with particular difficulties in getting children to eat allergenic foods.

“But it is the best way right now to diagnose food allergy,” she said. “You just have to do it in a safe manner and follow the food challenge guidelines.”

Crain also recommended collaboration with other providers in food allergy.

“Talking to them about their experiences is going to help you learn what you need to do,” she said.

Despite these challenges, Crain said the efforts are worthwhile as patients who pass can add more foods to their diets.

“It can improve their quality of life,” she said. “It is hard, but it can be done.”