No abstract

A diagnostic work-up should be performed in all children with non-immediate reactions to BL, to remove a false label of hypersensitivity. Even though only 57 (5.5%) of 1026 children displayed positive responses to delayed-reading intradermal tests to BL, such tests appear to be useful in order to reduce the risk for positive DPTs.

Penicillins and cephalosporins are the most important betalactams inducing IgE-mediated reactions. The safety of administering cephalosporins to penicillin-allergic children is a particular problem, because cephalosporin allergenic determinants have not been properly identified. A study was undertaken to evaluate the frequency of anaphylactic reactions to cephalosporins and penicillins and their cross-reactivity in a pediatric population. A prospective survey was conducted in a group of 1170 children with suspected immediate allergic reactions to cephalosporins and/or penicillins, which were examined during a period of 8 yr. In vivo (skin tests and challenges) and in vitro tests (for specific IgE) were performed with standard concentration of penicillins and cephalosporins. When 1170 children with a clinical history of allergy to penicillins and/or cephalosporins were tested in vivo for immediate hypersensitivity to betalactams, 58.3% cases overall were found to be skin or challenge test positive. Among them, 94.4% patients were positive to penicillins and 35.3% to cephalosporins. The frequency of positive reactions in the in vivo testing was in the range from 36.4% to 88.1% for penicillins and from 0.3% to 29.2% for cephalosporins. However, 31.5% of the penicillin allergic children cross-reacted to some cephalosporin. If a child was allergic to a cephalosporin, the frequency of positive reactions to penicillin was 84.2%. The cross-reactivity between cephalosporins and penicillins varied between 0.3% and 23.9%. The cross-reactivity among different generations of cephalosporins varied between 0% and 68.8%, being the highest for first and second-generation cephalosporins and 0% for third generation cephalosporins. The frequency of immediate allergic reactions to cephalosporins is considerably lower compared to penicillins, and the degree of cross-reactivity between cephalosporins and penicillins depends on the generation of cephalosporins, being higher with earlier generation cephalosporins. The cross-reactivity among cephalosporins is lower compared to cross-reactivity between penicillins and cephalosporins.

MDH can occur in children, even to drugs other than antibiotics. It is crucial to evaluate children with histories of MDH using both in vivo and in vitro allergologic tests, including challenges. In fact, such approach allows the physician to confirm the diagnosis of MDH in a small percentage of children with histories of MDH, as well as to rule it out in the great majority of them.

In line with the observed effects of food cysteine proteases in occupational allergy, these results suggest that disruption of tight junctions by food cysteine proteases may contribute to the process of sensitization in food allergy.