Pollen Food Allergy Syndrome (PFAS)

​PFAS, also called oral allergy syndrome, occurs when pollen sensitive individuals eat raw fruits, vegetables, or some tree nuts. It happens because the offending protein in the pollen is also found in the food (or something that closely resembles it). Thus, eating the food sets off a reaction because the immune system thinks it's found the pollen it's sensitized to. Cooking the food changes the protein structure so sensitive people can usually eat the food without suffering a reaction.

It rarely occurs in children under 3 but becomes more common as they grow older. It typically happens all at once, with foods they’ve been eating all their life with no problem.

For the technically-minded, PFAS is a type 1 reaction medicated by IgE antibodies.

Symptoms

Symptoms of PFAS include swelling of the lips, tongue, throat, and mouth; itchy mouth; scratchy throat; occasionally hives (on the mouth) and itchy ears. Symptoms typically disappear shortly after the food is swallowed and symptoms away from the mouth, or anaphylaxis for that matter, are rare. Some may occasionally experience more severe symptoms like nausea and vomiting. Because symptoms are typically mild and self-limiting, the true incidence is unknown.

PFAS can progress to more serious, systemic symptoms in up to 9% of sufferers and to anaphylaxis in up to 1.7%, in one study. 

Triggers

Of course, not everyone with these pollen sensitivities experiences PFAS when eating one or more of these potentially offending foods:

Birch pollen (likely the most problematic pollen): plum, pear, celery, cherry, apple, almond, carrot, hazelnut, kiwi, peach

Grass pollen: tomato, melon, orange, peach, celery

Ragweed pollen: cucumber, melon, zucchini, banana, sunflower seeds

Diagnosis

Typically made after taking a thorough history, and perhaps some scratch tests or oral food challenges with the suspected foods.

Medical Management

Avoidance. If one has PFAS and can’t eat a food cooked, typical with melons, it’s best to avoid eating the food altogether. (This is the standard medical advice, but one would think that times when the pollen they’re sensitive to isn’t present, the food could be safely eaten.) Since most symptoms disappear quickly, medical treatment is typically not necessary.

SET-DB™ Considerations

Clearing the pollen sensitivity should end PFAS reactions. It may or may not be necessary to clear the offending foods. One could always run a scan on the suspected foods to see what dRs are produced and go from there.

Comments

While in practice, I had a few patients complain of tingling of the mouth, tongue, or throat after eating a food, typically banana or avocado. It was rare, though. Clearing the food stopped the reaction, so it’s likely they didn't have PFAS.

Something similar may happen to people sensitive to latex, the proteins of which are found in foods like kiwi, chestnut, avocado, and banana. Symptoms are similar to PFAS, but since latex gloves have largely been removed from healthcare environments, latex food syndrome is rare. (Latex balloons are still around, though.)