Order IgE Testing Only for Chicken Allergy Evaluation
For a patient 5 days after an acute allergic reaction to chicken, you should order chicken-specific IgE testing only—not IgG. IgG testing has no role in diagnosing IgE-mediated food allergies and should never be ordered for this purpose 1, 2.
Rationale for IgE Testing
IgE antibodies mediate acute allergic reactions to foods, including chicken meat, causing rapid-onset symptoms (minutes to hours) such as urticaria, angioedema, respiratory symptoms, gastrointestinal complaints, and potentially anaphylaxis 1, 3.
Serum-specific IgE testing is appropriate when evaluating suspected IgE-mediated food allergy, particularly when the clinical history suggests an acute allergic reaction with typical symptoms occurring shortly after chicken ingestion 1, 2.
The 5-day timeframe is appropriate for IgE testing, as specific IgE antibodies persist in the serum and are not affected by the timing relative to the acute reaction 1.
Why Not IgG?
IgG antibodies to foods are not diagnostic of food allergy and merely indicate prior exposure to that food protein—they are found in both allergic and non-allergic individuals 1.
No established guidelines recommend IgG testing for food allergy diagnosis, and such testing can lead to unnecessary dietary restrictions and misdiagnosis 1, 2.
Diagnostic Approach
The complete diagnostic workup should include:
Detailed clinical history focusing on the temporal relationship between chicken ingestion and symptom onset, symptom pattern (dermatologic, respiratory, gastrointestinal, cardiovascular), and reproducibility of reactions 1, 2.
Serum chicken-specific IgE testing as your laboratory investigation of choice 1, 2.
Consider skin prick testing (SPT) as an alternative or complementary test, which has higher sensitivity than serum IgE testing, though serum testing is appropriate when SPT is contraindicated or unavailable 2.
Important Caveats
A positive IgE test indicates sensitization, not necessarily clinical allergy—correlation with clinical history is essential, as positive tests without clinical symptoms only demonstrate sensitization 1, 2.
Chicken meat allergy is rare and can occur without concomitant egg or feather allergy, particularly in adults and adolescents 4, 5, 6.
Cross-reactivity exists between chicken and turkey meat, and patients may also have concomitant allergies to fish and shrimp 5, 6.
Referral to an allergist is mandatory after any suspected anaphylactic reaction for comprehensive evaluation, potential oral food challenge if diagnosis remains uncertain, and development of an emergency action plan 2.
Post-Testing Management
If IgE testing is positive and correlates with clinical history, prescribe an epinephrine auto-injector (two doses), provide an anaphylaxis emergency action plan, and refer to an allergist for ongoing management 1, 2.
If testing is negative or equivocal, allergist referral for supervised oral food challenge may be necessary to definitively establish or exclude the diagnosis 1.