Our son is allergic to nearly everything (peanuts, nuts, dairy, eggs, sesame, wheat) and we haven't found an allergist willing to work with us. Do you know if there's an age factor for immunotherapy effectiveness? He's 2 1/2 yo.
Age is a known factor for oral immunotherapy’s risk and effectiveness, and the commonly cited fuzzy threshold is starting before 2 years of age. The data isn’t that strong, but “start very young” basically has practitioners’ consensus.
You have to shop around for allergists willing to do it. Our first allergist told us they weren’t comfortable doing it but it was becoming an increasingly popular option and referred us to several allergists who did it. We’ve also spoken to allergists who were bearish on it. It’s because there’s very little published data.
2 1/2 is right in the window, with the general consensus being that the earlier you start, the better the results. Studies found the best results with 1-year-olds, then it exponentially decreases with each year, until there's little benefit with 4+ year olds.
We did it with Latitude [1], with the support of our allergist, who had sent his son through them with successful results. It's not covered by insurance, and is expensive in all of time, money, and attention. The field is very new and data is still sparse - our allergist actually was very curious to hear results because he's adapting his practice as new data comes out from actual treatment.