Our understanding of pollen food allergy syndrome (PFAS) and its relationship to typical food allergy symptoms and management has continued to advance. Researchers at the 2024 AAAAI Annual Meeting presented information on global and seasonal trends surrounding PFAS that may help guide optimal management strategies.

Following these presentations, featured expert Ruchi Gupta, MD, MPH, was interviewed by Conference Reporter Associate Editor-in-Chief Mona Shah, PharmD. Dr Gupta’s clinical perspectives on these findings are presented here.

PFAS, also known as oral allergy syndrome, is very common because environmental allergies are very common. PFAS is so interesting to me because so many people have it but think that it is a typical full-blown food allergy. You will sometimes hear from patients that they are “allergic to avocados or apples,” so you test them because those are not common food allergens. Often what they are really experiencing, however, is PFAS, which should lead to a conversation with them about it. It is really important to understand this syndrome and to educate patients. I love educating people about the differences between PFAS and true food allergies because it can be freeing for them to understand that they are not allergic to the food that they thought they were allergic to.

PFAS is IgE mediated, and the primary reaction occurs because of cross-reacting allergens between the pollen and similar proteins in the food (class II food allergens). Interestingly, symptoms are typically very localized because the class II food allergens are interacting with the oropharyngeal mucosa. People can get hives, usually around the mouth, and typically feel itching and tingling in the mouth right away. And then some people experience throat tightness and a little bit of hoarseness. But symptoms are all usually isolated to the oral area, and they usually do not last very long. After the person stops eating the food, they typically go away quickly. Conversely, with a typical food allergic reaction, you can have symptoms in any body system, such as skin reactions, throat closing, oral symptoms, vomiting, trouble breathing, and, potentially, a drop in blood pressure. Pretty much any organ system can be impacted.

As noted previously, for most of the population, PFAS will just cause oral symptoms and never lead to anything more severe; it is typically not as severe as traditional food allergies. With PFAS, I used to not necessarily restrict the food that was causing trouble. Instead, I would sometimes recommend taking an antihistamine before or after exposure, along with telling patients to cook the food before eating it. Lately, however, we have been hearing more about people having systemic reactions in a minority of cases. So, the management of PFAS is something that is currently being debated.

There was a talk at the 2024 AAAAI Annual Meeting by Ramon et al about anaphylactic episodes in patients with PFAS, especially with foods such as peaches, which was very new to me and is something that they are seeing in Europe. It is fascinating for us to learn from this and to investigate if there are specific foods that may cause more severe symptoms and if symptoms are impacted by the amount of pollen taken in (ie, is there a seasonality to it?). The big questions that arose were: Do you prescribe epinephrine? Should these people be worried? Should they really completely avoid that food?

An abstract from Japan on allergen profiles in children with PFAS was presented at the AAAAI meeting (abstract 096). It identified PR-10 proteins as the most common allergen. Another abstract reported an in vitro and murine model to identify unknown cross-reactive allergens (abstract 094). I think that they are finding ways to test it better, which is great.