Oral challenge to document loss of alpha gal allergy
Question:
9/16/2020
A 54 year-old male, PMHx mild persistent asthma and allergic rhinitis (both well-controlled) was diagnosed with alpha gal hypersensitivity after a tick bite in 2013. Initially, he developed generalized hives and mild dyspnea about three hours after ingestion of pork. His symptoms resolved with OTC Benadryl in a few hours, and he did not seek medical attention. He has avoided all mammalian meat up until this year when he accidentally ate bacon (unknown amount) without any issues.
Serum testing as follows:
2013 2016 2020
Alpha gal 6.21 2.69 0.23
Beef 2.39 1.05 0.13
Pork 1.58 0.96 <0.10
Mutton 1.31 0.70 <0.10
(all above IgEs in kU/L)
He queries if his meat allergy has resolved. I am requesting guidance how to proceed with respect to oral challenges to assess if patient has lost clinical sensitivity to mammalian meat/alpha gal hypersensitivity.
Answer:
A series of oral challenges with a usual sized serving of the specific implicated meats and then at least four hours of observation would be indicated. I would probably start with pork. A positive challenge would be expected to result in symptoms similar to the index events. This could be safely done in any setting where you would do a peanut or amoxicillin challenge.
I hope this is helpful.
Eric Macy, MD, MS, FAAAAI