Routine laboratory determinations in pediatric allergic disease.

Clinical and laboratory data were extracted from the medical records of 285 consecutive children after completion of their evaluations for suspected atopic disease. Blood eosinophilia, determined from a routine complete blood count, was present in more than 60% of patients tested. Nasal smear for eosinophils or a direct eosinophil count provided little additional evidence of atopic reactivity in simultaneously tested patients. Total serum IgE concentration was elevated in 75% to 81% of the children with asthma, nasal allergy and atopic dermatitis and an elevated serum IgE concentration or blood eosinophilia, or both, was noted in 85% of the patients studied. Selective IgA deficiency was documented in three children and hyperimmunoglobulinemia was found in 20 others. Serum complement activity was normal in 10 children with persistent urticaria, allergy, IgE, eosinophilia, immunoglobulins, complement.