Methods: Retrospective chart review of all children undergoing OFC to any food excluding milk, egg, peanut, wheat and soy from 2004-2012.
Results: Patients aged 1-18 years (median 6) underwent 366 OFCs. Challenged foods included tree nuts (36.6%), meats (15.8%), seeds (11.7%), shellfish (9%), fish (6.8%), fruits and vegetables (6%), grains excluding wheat (5.7%), legumes excluding peanut (4.9%), and miscellaneous foods (3.2%). 90.7% of patients had other FA, 71.6% asthma, and 48.1% eczema. Overall, 81.1% of children passed OFC with similar pass rates within each food category. Only 6.3% of challenges required epinephrine administration. Highest pass rates were among OFCs to miscellaneous foods (91.7%) and lowest to grains excluding wheat (71.4%). Failure rate was associated with history of other FA (OR 8.2, P<0.04), but there was no correlation to age, history of prior reaction, time since last ingestion, or history of asthma or eczema. Wheal size was slightly larger in those who failed (5mm vs. 4mm), and this was markedly significant (OR 1.16, P<0.0001).
Conclusions: FA to uncommon allergens is becoming increasingly prevalent. Patients with other FA are more likely to have true allergy to these foods. Overall, pass rates appear to be significantly higher than OFCs to milk, egg, peanut, wheat and soy, suggesting that allergy to these uncommon foods may be overdiagnosed.