Allergy can be identified through a three step process:
Diagnosing allergy starts with a physical examination and an allergy-focused patient history. Asking just a few key questions will provide you with a detailed history, (for food allergy, indicate if the allergy is IgE- or non IgE-mediated) and allow you to correctly manage your patient. The key questions should focus around:
- Patient, environmental and family history
- Suspected allergens
- Time course between exposure and symptoms
Assess the need for testing
If the patient history suggests an IgE-mediated allergy, conduct a blood test (allergen-specific IgE) or by trained, competent clinical staff, in an environment with facilities to manage anaphylaxis5 Specific IgE testing can be performed on any patient irrespective of age, allergic symptoms (i.e. eczema) and medication.
Download a clinical toolkit to learn more about which allergens to test for.
When taking blood for a test a 1 ml sample of whole blood is sufficient to test for up to 10 different allergens.
Interpretation of test results
Results should be read in conjunction with the clinical history.
Avoidance or reduction in exposure to allergens can alleviate or reduce symptoms.
In food allergy, in consultation with a dietitian, the food should be removed from the diet. In aero allergy, symptoms can be managed with medication, however, patients, particularly patients with asthma, could be at risk of severe reactions and as such advice should be given on reducing these allergens from the environment.5
For management tools view the resources section.
Case history alone is not enough - don't guess, test
Adapted from Duran Tauleria, 2004 and Niggemann 2008. Allergy 2004;59 (suppl 78): 35-41 and Pediatr Allergy immunol 2008; 19:325-331. Study among patients with symptoms of eczema, wheezing and/or asthma, and rhinitis in primary care.3,4
By adding the above considerations to an IgE antibody test result, combined with previous medical history and a physical examination, the allergy investigation can be fine-tuned to give a highly informative picture.