A small study published in The Journal of Allergy and Clinical Immunology: In Practice sought to determine the long-term effects and safety of oral immunotherapy (OIT) for the treatment of adults with milk, peanut, or egg allergy and examine the predictive factors for terminating OIT.
The researchers assembled a cohort of 30 individuals aged 18-64 who received OIT for milk, peanut, or egg allergies at Helsinki University Hospital, whose food allergies were diagnosed based on their clinical history, allergen-specific IgE levels, and oral food challenges (OFCs).
They compared baseline and 2-year post-start allergen-specific IgE levels and the highest tolerated dose in participants who had received 2 years or more of OIT. They also compared the sex, baseline allergen-specific IgE levels, lung function, highest tolerated dose, and age of the 14 participants who completed two or more years of OIT and the 16 who stopped OIT before the 2-year mark.
OIT did provide desensitization for those able to reach the 2-year threshold, which included 7 with milk allergy, 5 with peanut, and 2 with egg allergies. They saw an increase in tolerated allergen dose of 50-fold for milk, 600-fold for peanuts, and 420-fold for eggs. The trend for these individuals was a decrease in allergen-specific IgE levels.
Of those who continued OIT for 2 years or longer, 13 reported local itching or swelling, 11 itching of the mouth or throat, 6 angioedema (swelling), 9 eczema, 2 generalized urticaria (hives), 7 abdominal pain, 6 nausea, 2 vomiting, 1 diarrhea, 10 asthma symptoms, 2 epinephrine injection usage, and 4 emergency department visits due to OIT. Epinephrine usage was reported by 29% of the milk allergy group although not used by the peanut or egg allergy groups. Emergency department visits due to allergy was reported by 43% of the milk group and 20% of the peanut group with no such visits were reported by the egg group.
Reasons for discontinuation were social (moving to a different city or abroad, pregnancy, lack of time and energy for OIT) in 7 of 16, adverse events in 10 of 16, and repeated infections in 1 of 16. In 1 of 16, follow-ups were moved to primary health care, and further data were missing. A dropout may have multiple reasons for terminating OIT. In the milk allergen group, those who stopped OIT were younger — a median age of 25 years— than those who continued OIT for 2 years or longer.
The researchers determined their real-life pilot study showed success rates of OIT in adults are limited. However, OIT increases tolerance in the long term and most adverse events are mild.
They did find an indicator that may serve as a predictor for OIT success: Pre-fractional exhaled nitric oxide levels were double in the individuals who stopped OIT before the 2-year mark than those who reached that goal.
