<p>A major worry for patients with food allergies is the accidental exposure to allergens and the consequences of that exposure. Finding the threshold doses of a specific food allergen may assist with the development of a strategy to try to partially desensitize the patient and perhaps provide a measure of protection in the case of accidental exposure.</p>

As clinicians, our approach to patients with food allergies has changed over the years and will continue to do so. Years ago, the dogma was that patients only outgrew their food allergies if they maintained strict avoidance. We later learned that the addition of baked milk and baked eggs to the diets of milk- and egg-allergic patients actually improved their likelihood of outgrowing their allergies. Both in research and in clinical practice, we are now learning that utilizing threshold dosing may be a potential approach to the management of food allergies and that small, controlled exposures to allergens may be helpful for some children and may actually help them outgrow their allergies, similar to the concept of oral immunotherapy.

 

A threshold dose is the amount of an allergen (cumulative amount) that leads to a reaction. Threshold doses have been used predominantly in research studies. More recently, however, we have also been able to determine these threshold amounts during oral food challenges (OFCs). We do know that cofactors such as concurrent illness, exercise, and NSAID use may influence this threshold amount, and research into other potential cofactors is ongoing.

 

With the use of threshold doses, the question that will be answered over time is: Is there is a way to safely give a patient a smaller amount of a food (less than the threshold dose) to keep them safe from an accidental exposure or to even help them outgrow their food allergy? At times, I will use threshold dosing in this way. For example, if a child reacts during a peanut OFC to an amount that is equivalent to 4 peanuts, then perhaps having that child introduce 1 peanut per day into their diet may be helpful both for protection against accidental exposure and to increase the likelihood of developing tolerance. I would feel more comfortable incorporating threshold dosing in someone who has an allergic reaction that only involves the development of hives at the end of an OFC vs in someone who, on the first or second dose, needs epinephrine to treat their reaction. We will discuss these options with patients and their families, reviewing the potential risks and benefits.

 

I think that, clinically, this can be difficult for allergists, depending on whether they perform OFCs. If an allergist does not perform OFCs, it is hard to know with the current IgE and skin testing what dose of an allergen someone may or may not tolerate. But, if an allergist does perform OFCs, it is important to keep track of how many milligrams of the allergen the person is getting so that we can recognize the threshold dose. Real-world use is different than studies, and more research is needed to confirm what has been seen to date.