Case report: Milk oral immunotherapy for adult-onset cow's milk-induced anaphylaxis.

While food allergies affect individuals across all age groups, oral immunotherapy (OIT) has been widely studied and implemented in pediatric populations. Here, we report a successful case of cow's milk (CM) OIT in a 60-year-old male with adult-onset cow milk allergy. The patient who was previously tolerated with CM initially presented with generalized pruritus, rash, dyspnea, urticaria, and dizziness occurring 4 hours after consuming milk-containing foods. The patient was positive on the skin prick test and for specific IgEs to milk (24.4 kU/L) and casein (31.2 kU/L). After diagnosis, CM OIT was initiated using bread containing milk protein. The protocol began with a 1/4 slice of milk bread (1.55 g of milk protein) and gradually increased to 1 full slice (6.2 g of milk protein) over the course of 4 years. Throughout the period, the patient's immunological markers consistently improved, with his CM-specific IgE level decreasing from 24.40 to 1.50 kU/L and his casein-specific IgE level decreasing from 31.20 to 2.24 kU/L. The patient successfully completed an oral food challenge with 190 mL of cow milk and currently maintains a daily consumption of 200 mL of CM without adverse reactions. This case demonstrates that CM OIT can be successfully implemented in elderly patients with adult-onset CM allergy. The clinical and immunological responses suggest that immune modulation remains possible even in older adults, suggesting potential therapeutic options for adult-onset food allergies.