How do you perform an in-office graded oral challenge in a child to investigate for possibility of IgE-mediated food allergy who has chronic spontaneous/idiopathic urticaria and angioedema?
I have a 2 yr & 10 month old white male who has CIU/A that both a previous allergist and I diagnosed. Patient has nasal allergies and atopy with a few aeroallergen skin tests positive, but no major rhinitis, no asthma, and no eczema. The child has gotten red spots that look like hives to the mother when certain foods touch his skin (chicken, turkey, egg) and has gotten peri-oral red spots soon after eating mustard (but sometimes eats mustard and has no red spots). The previous allergist did IgE testing to foods and some foods had positive IgE tests. Turkey, chicken, egg white, and mustard were positive. I repeated the in-vitro IgE to those foods, and they are still positive-- turkey IgE= 0.52, egg white IgE = 0.57, chicken IgE= 3.03, mustard IgE= 0.61. Only chicken is above 1.00. The previous allergist performed a graded in-office food challenge to turkey. The challenge was positive because eyelid swelling, red spots occurred on face and child had a lot of throat clearing. No wheezing, GI, or CV sx. The child was labeled with turkey allergy but he also has hives and eyelid swelling occurring spontaneously, which is why the allergist and I diagnosed him with CIU/A. So, the sx that occurred during that turkey challenge may have been coincidental and unrelated to turkey ingestion.
Should I do another turkey, chicken, mustard, and egg challenge on separated days? I would like to, but should the child be on antihistamines? If he does not take daily antihistamines, then he may get hives/eyelid swelling that occurs spontaneously during the food challenge. If he does take antihistamines up to and on the day of food challenge to prevent his spontaneous hives and has no sx during my food challenge to turkey then an allergist could accuse me of coming to a false-negative conclusion because the antihistamines could have theoretically masked his allergic reaction to that food. So, I am in a quandary. What would you do this situation?