- Medical history that would prevent a DBPCFC (double-blind placebo-controlled food challenge) to egg. The medical history that would prevent the DBPCFC to egg would be a prior history of an open egg challenge in which the patient experienced hypotension which required fluid resuscitation, respiratory compromise which necessitated ventilatory support, or poorly controlled asthma as evidenced by an FEV1 < 80% of predicted, or FEV1/FVC <75%, with or without controller medications