Peanut hypersensitivity in children

Abstract

Peanut is the major allergen in the United States. It is increasing in importance in Europe and has become the principal food allergen affecting children over the age of three years, once hypersensitivity to eggs has resolved. We report 132 pediatric cases of peanut hypersensitivity, confirmed by food challenge. The study group included 86 boys and 46 girls aged between 6 months and 15 years. More than half the children with peanut hypersensitivity were diagnosed before the age of three. The most common symptom was atopic dermatitis (43.1% of cases). The other symptoms observed were hoarseness (34.8%), asthma attacks (13.6%), anaphylaxis (6%), gastrointestinal symptoms (1.5%) and oral syndrome (0.7%). All patients had positive skin prick tests, with a mean wheal diameter of 8 mm (range: 2 to 25 mm). Wheal diameter was significantly smaller in the youngest children (mean 4.5 mm for children under the age of 1 year, p < 0.01). Specific IgE concentration was below 0.75 IU/ml in 16 cases (14.3%), the mean for the entire group being 30.9 IU/ml (range: 0.75 to 100 IU/ml). Food challenges were not performed in three of the eight children with a history of anaphylaxis. Labial food challenge (LFC) was positive in 85 cases (64.8%). An oral food challenge (OFC) was carried out for 45 children (34.3%) and the mean reactive dose was 850 mg (range: 1 mg to 7g). LFC with peanut oil was positive in 2 cases of 50 tested (4%) and 17 of 63 children (29.9%) tested by OFC were also found to be sensitized to peanut oil. Half the children were also hypersensitive to other foods, as demonstrated by oral challenge (53.7%) or sensitized to airborne allergens (62.8%). Hypersensitivity in the very youngest children raises questions about how sensitization occurs. Diagnosis was confirmed by food challenge. Peanut products are very difficult to eliminate from the diet because of inadequate labeling of food products. An ELISA test, available in a number of countries, can be used to detect the allergen.