We describe a 20-month-old girl with hypereosinophilia, hyper-immunoglobulin (Ig) E syndrome, and atopic dermatitis. Her peripheral eosinophil count and IgE plasma levels were 2.65 x 10(9)/L and 6702 IU/mL, respectively. Specific IgE levels for a variety of foods and inhalants were high and single-blind food challenges were positive for cow's milk, hen's egg, oat, wheat, and soy. When the patient received an extensively hydrolyzed milk formula, an exclusion diet, and 2 mg/kg of prednisone daily, the atopic dermatitis partially improved. Further improvement was observed with 1 mg/kg of azathioprine daily. Long-term clinical response was satisfactory. We suggest that food hypersensitivity should be ruled out in patients with hypereosinophilia, hyper-IgE syndrome, and atopic dermatitis. Azathioprine may be a good therapeutic alternative for treatment in such cases.