Allergic Reactions Associated with Ingestion of Protein Supplements

Supplemental whey protein products and other concentrated dietary protein supplements are increasingly used and represent a potentially unrecognized cause of food allergy. A case series of 4 patients evaluated for a combination of immediate symptoms including urticaria, angioedema, bronchospasm, pre-syncope and gastrointestinal distress. During the evaluation each patient noted ingestion of a dietary protein supplement in close proximity to the onset of symptoms. A total of 4 patients were skin prick tested to the exact protein product which potentially elicitedtheir reaction. This was done by the “prick-prick” method once the protein product had been made into solution with saline. Three patients demonstrated a wheal >3mm of saline control to the dietary protein product. All 3 patients with positive skin prick testing reacted to a whey protein product,but 2 patients continue to tolerate traditional cow’s milk products (i.e.milk with cereal). There was one patient who did not show sensitization to the protein product tested. Each dietary product was tested in duplicate by “prick-prick” on control subjects without demonstrating dermal reactivity. Ingestion of concentrated dietary protein supplementation products may result in allergic reactions. These reactions appear to be unique to the whey protein supplement rather than a global cow’s milk allergy. There may be factors associated with supplement preparation and processing which result in more immunogenic antigens in these highly concentrated protein products. We suggest questioning patients about the use of protein supplements when presenting with symptoms suggestive of an IgE mediated food allergy.