There are many factors to consider when deciding whether to pursue OIT. The decision to start OIT is, in part, dependent on the family, the specific food allergen, and the child’s presentation and reaction history. Another consideration is the natural history of food allergies. We know that some food allergies usually resolve spontaneously by the time the child reaches school age. Based on natural history studies, we know that milk and egg allergies are more likely to resolve on their own, whereas peanut, tree nut, and seed allergies tend to persist.

Allergic children present with different phenotypes. For example, consider a 2-year-old child with milk and egg allergies, multiple allergic comorbidities, multiple accidental exposures resulting in allergic reactions (including anaphylaxis), and high baseline serum immunoglobulin E (IgE) specific to the food. Further, the child does not tolerate milk or egg in baked form. In this scenario, this child is less likely to outgrow their food allergies, even though the natural history data may suggest a relatively high rate of natural resolution in the overall population. If the allergy-related burden is high, and if there are multiple reactions to trace amounts of the culprit food, then it is reasonable to consider intervening earlier.

Conversely, if a child is tolerant of the baked form of a food to which they are allergic and has not experienced significant reactions, has no other allergic comorbidities, and has serum-specific IgE levels that are low and are declining over time, then it may be better to wait and see if they will outgrow the allergy. However, cases in younger children are seldom simple or straightforward, and OIT is an important consideration that needs to be explored in detail with the patient and family.

For milk and eggs, allergists may conduct an oral food challenge (OFC) with baked milk or baked egg for children aged 1 to 2 years or older. If the child tolerates the challenge, then they are, in a way, receiving a form of OIT that they can receive at home without the traditional updosing that occurs with other OIT. If their child fails the baked milk or egg challenge, parents may want to consider milk or egg OIT with the unbaked forms of these foods. Ultimately, it is a process of shared decision making, a part of which involves the parents’ consideration of whether OIT fits in with their goals and whether they want to manage the potential reactions that may occur with OIT.

Peanut allergies are different, since only 20% to 25% of peanut-allergic children outgrow this allergy. There is a rationale for being more aggressive with older infants and toddlers who fail early introduction to peanuts because they may be candidates for early OIT. As Dr Anagnostou pointed out, a child’s immune system is probably more malleable early on. If you catch peanut allergies early, you may be able to increase the number of patients who outgrow the allergy. Early OIT may be successful for a number of common food allergies, but it has been studied less in these younger children.

Finally, the setting in which OIT takes place matters. Clinicians who are working in academic centers may have more resources for OIT than those in other settings. OIT may not be suitable in some practices that are not equipped to perform OFCs safely, especially for our youngest patients. If there is no capacity to perform OFCs, OIT should not be administered at that setting.

The decision to start OIT or to wait and see if the child outgrows a food allergy is also allergic phenotype driven, as my colleagues suggested. A large percentage of children with milk and egg allergies will naturally outgrow them. Conducting OFCs, monitoring IgE levels, and performing skin tests are essential. I would reiterate the importance of introducing the baked form of milk or egg, which can truly be a form of OIT. Studies have shown that allergic children can outgrow a milk or egg allergy more quickly if they receive and tolerate the baked product because the food proteins are denatured by baking and are then much less likely to cause reactions. A baked food challenge is routinely completed to identify children who might be able to have milk or eggs in the baked form as a means of initiating the introduction to that food.

IgE and skin testing are also especially important in younger children and can be done on an annual basis to identify the likely prognosis of an individual patient. With regard to milk and eggs, a patient with a more severe allergy will usually have much higher IgE levels and more pronounced areas of sensitivity on skin testing, both of which may indicate a more persistent food allergy. This is different from a child with a meager reaction history and mild results on skin tests and in their blood work. The milder the response, the more likely the child will outgrow their allergy.