Objective Prevalence rates for specific food allergies are increasing. The gold standard investigation has been the double blind, placebo controlled food challenge (DBPCFC). Skin prick testing (SPT) and food specific IgE levels are alternatives but do not have acceptable sensitivities and specificities to permit reduction in rates for DBPCFCs.
Methods A retrospective chart based audit collated results for oral food challenges, SPTs and food specific IgE levels in patients referred to a hospital paediatric allergy service. Indications for tests, results and risk management issues were recorded. Results for oral food challenges were compared with those from SPTs and IgE levels.
Results Challenges with peanut, milk, egg yolk and egg white were positive in 30% of tests. Eighteen percent of challenges had no clear indication documented. Protocol compliance was high but there were omissions in crucial risk management areas including informed consent, pre-challenge medical checks, intravenous cannulation and supervision of challenges including observation records. Some challenges were carried out despite SPT and specific IgE levels indicating a high risk of serious allergic reaction. Predicting when a challenge should follow a SPT or food specific IgE level on any patient could not be made.
Conclusions Further large prospective studies measuring SPTs, food specific IgE levels and results for DBPCFCs might enable cut-off points to abort unnecessary food challenges. Allergy units could agree on a united protocol for challenges and pool results to strengthen audit conclusions and avoid omissions in crucial risk management issues.