Oral food challenge: safety, adherence to guidelines and predictive value of skin prick testing.

Background: The diagnostic gold standard of food allergy is the oral food challenge (OFC). Data on severe reactions and drug use during OFC are scarce. Our aims were (i) to investigate the prevalence and spectrum of reactions' severity during OFC and to assess drug use and epinephrine use in anaphylaxis due to OFC; (ii) to investigate the predictive value of the skin prick test wheal size for the outcome of OFCs.

Methods: A retrospective charts review of children undergoing OFC at three Allergy Centres between January 2007 and December 2008 was performed.

Results: A total of 544 OFCs were analysed. Most frequently involved foods were egg, milk and wheat. 254/526 (48.3%) were positive. 167 (65.7%) were defined mild reactions, 81 (31.9%) multiorgan reactions and 6 (2.4%) anaphylaxis. No patients had cardiovascular symptoms. Data on treatments were available in 98.8% OFCs. In half of them antihistamines were used vs. 10% cases in which steroids were preferred. Six children (2.4%) were treated with Epinephrine inhalation, 5 (2%) with beta-2 inhalation, 8 (3.1%) with steroid inhalation. One child was treated with IM Epinephrine + IV fluids. Skin prick tests predictive cut-off were 9 mm for albumen, 7 for yolk, 13 for fresh albumen, 10 for α-lactalbumin, seven for casein, eight for β-lactoglobulin, 20 for cow's milk and 10 for fresh cow's milk.

Conclusion: OFCs performed in controlled settings by expert Allergists are safe. Consideration needs to be given as to whether the Anaphylaxis' Guideline need to be modified when applied in treating patients undergoing OFC.