Different studies proposed specific
immunoglobulin E (
IgE) cut-off levels for the diagnosis of
egg allergy. Little is known if
IgE titres could be helpful for prediction of the severity of the reaction. The aim of this study was to determine whether
IgE titres are associated with the severity of the reaction during a standardized egg challenge. We reviewed data obtained during oral challenge tests to egg performed between 2003 and 2005, and attributed a clinical score to the positive reactions. Serum specific
IgE levels were analysed in relation with the severity of the reaction. We analysed data from 51 oral food challenges to egg, raw or cooked. Sixteen challenges (31%) were negative and 35 (69%) were positive of which 13 challenges (37% of positive reactions) elicited a severe reaction.
IgE levels in our patients ranged from undetectable to 14.90 kU/l. We could determine a cut-off level of 8.20 kU/l for a 90% probability of clinical reactivity.
IgE titres were statistically significantly different between the patients with absent, mild and moderate or severe reaction. Patients with negative challenge had
IgE levels between 0.35 and 6.41 kU/l (median 1.17), those with mild and moderate reaction had
IgE levels ranging from 0.35 to 14.90 (median 2.47) and patients with severe reactions had
IgE between 1.18 and 11.00 (median 3.70) (p = 0.006). Our results show a correlation between
IgE titres and the severity of the clinical reaction to egg.
IgE titres may help to determine the potential risk of a reaction to eggs.