New products on the horizon to prevent food-induced anaphylaxis

Issue: June 2008

Food-induced anaphylaxis is an acute, life-threatening reaction that is underreported, frequently misdiagnosed and undertreated, according to Stacie Jones, MD, associate professor of pediatrics at the University of Arkansas for Medical Sciences.

“Epinephrine is first aid for anaphylaxis, and it requires rapid, proper administration,” said Jones, who spoke on this topic recently at the 2008 Annual Meeting of the Pediatric Academic Societies, held in Honolulu.

Understanding anaphylaxis

In 2005, a group was convened by the NIH and the FDA to discuss anaphylaxis. The group defined anaphylaxis as “a generalized allergic reaction that is rapid in onset and may progress to death.”

According to Jones, the criteria for the diagnosis of anaphylaxis are divided into three sets, and anaphylaxis is likely when any of these sets of criteria are met:

Acute onset of illness (seconds to minutes) with involvement of the skin, the mucosal tissue and at least one of the following: respiratory compromise or reduced blood pressure or associated symptoms of end-organ dysfunction. Eighty percent of anaphylaxis cases meet these criteria.
Two or more of the following that occur rapidly after exposure to a likely allergen for that patient, including skin symptoms, mucosal tissue symptoms, respiratory compromise, persistent gastrointestinal symptoms or reduced BP or associated symptoms.
The third set strictly diagnoses anaphylaxis based on BP findings, including a reduction in BP after a known allergen exposure for that patient, which occurs very rapidly. These criteria are different for children and adults and include a greater than 30% drop in systolic BP.

Food is the most commonly identified cause of anaphylaxis in emergency department and hospital studies, accounting for approximately 30% of anaphylaxis cases. Peanuts and tree nuts account for more than 90% of fatalities, but any food allergen can result in fatality.

Other common foods that cause anaphylaxis are shellfish, milk and eggs.

“Based on our limited registries, there are estimates of approximately 150 fatalities from food-induced anaphylaxis due to these agents that occur in the United States per year, and this is likely underreported,” Jones said.

She indicated that there have been several reports that have examined the incidence of fatal and near-fatal reactions. The features that are common in all of these studies are that most patients present with their symptoms within the first 20 minutes after exposure and progress rapidly to death within one to two hours.

Most patients are not in their homes when the reaction occurs, and they may not know that the food they are consuming contains the allergen.

Another troubling finding is that immediate symptoms occur typically within seconds to minutes, but about half of these patients have a quiescent period and then subsequent symptoms.

According to Jones, there are three phases of anaphylaxis. The initial phase occurs within seconds to minutes. There is a protracted symptom profile that occurs very early and continues during a 72-hour period; however, this is considered rare. In about 20% to 30% of cases, there is a second quiescent phase that occurs after the initial symptoms. Afterward, there is a biphasic reaction when the second phase of symptoms occurs. These symptoms could be similar to the ones in the first phase or could be more severe. “We need to think about this type of biphasic reaction when we are prescribing epinephrine and other therapeutic interventions and when we are educating our families,” she said.

Treating anaphylaxis

In the United States, two forms of autoinjectable epinephrine are available.

Adolescents and young adults comprise the highest-risk group for fatal or near-fatal anaphylaxis. A study conducted by Sampson et al included 174 teenagers aged 13 to 21 years and was conducted to gain insight into risk-taking behavior. Only 61% of these teenagers reported always carrying their epinephrine, despite the fact that they knew they had allergies. Additionally, 54% admitted to purposely ingesting potentially unsafe food, and 60% of teenagers told their friends about their food allergy.

Several new therapies are on the horizon for the treatment of food-induced anaphylaxis.

Products using humanized monoclonal anti-IgE therapy have shown significant benefit in the treatment of IgE-mediated disease related to asthma and allergic rhinitis, according to Jones.

Additionally, sublingual immunotherapy has been used successfully for inhalant allergens, and there is early evidence that this may be useful for food allergy.

“From a recent study, we have concluded that peanut oral immunotherapy provides protection from anaphylaxis and early evidence of immune deviation toward tolerance. Unfortunately, it’s not quite ready for prime time yet,” Jones said. – by Michelle Stephenson

For more information:

Jones S. Food anaphylaxis: management issues. #4192. Presented at: the 2008 Annual Meeting of the Pediatric Academic Societies; May 3-6, 2008; Honolulu.