How can doctors tell if somebody has an egg allergy?

History: If you have an egg allergy, you would probably know by now. So many food products have eggs (cake, cookies, etc.) that if you had an allergy... You would have probably had some symptoms at this time. The only sure way to know if you are not sure is to get tested. This can be checked with a simple blood test (rast) or via skin-prick.

Blood or skin test: A serum blood test or a skin test may detect the presence of allergic antibodies against eggs. That alone, however, is not enough to diagnose egg allergy. Sometimes, a person may harbor the anti-egg antibodies and still enjoy eggs without a problem. The next step would be to correlate your symptoms upon egg exposure with the results of the allergy testing to arrive at the correct conclusion.

Via an allergist: Consultation with a board-certified allergist and review of the clinical history are the most important factors of determining an egg allergy. For further evaluation and supportive evidence, the allergist may opt to perform skin testing and/or bloodwork to aid in the diagnosis.