Background The acquisition of new food allergy after transplantation (TAFA) is usually reported in adults and rarely in children.

Aim Here, a patient although who had normal total IgE and specific IgE test results, he developed reaction to skin prick test for cow’s milk after transplantation is presented and his clinical presentation will be discussed.

Case presentation 15 month-old- boy came to our allergy clinic with complaints of vomiting after drinking cow‘s milk and skin rush on the area where contacted with chocolate. In his past medical histroy, left lateral segment of liver (donor was his mother) was transplanted to him when he was at 5 months. Methylprednisolone and tacrolimus immunosuppression were used after the transplantation, and tacrolimus therapy was continued for prophylaxis of chronic rejection. When he was at 7 months, family fed the patient with cow’s milk but 3 h later he began to vomit. He was thought to be having food protein induced enterocolitis. His vomiting complaints repeated after intake of formula and baby food which includes grain. Laboratory findings: Total IgE : <5 and ImmunoCAP specific IgE against milk, grain and other classic foods was <0.35. Skin prick test.

Results saline: 0 × 0 mm, histamine 4 × 4 mm, fresh cow’s milk: 2 × 2 mm, other food allergens (peanut, egg, fish, soybean, wheat): 0 × 0 mm.

Conclusion Our patient seemed to have cow’s milk allergy related to liver transplantation. Laboratory investigations and clinical presentation of the patient did not look like typical IgE–mediated food allergy, which is expected in TAFA.