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A physician will perform a physical examination on a patient suspected of having angioedema. A complete medical history, including a list of symptoms and a complete list of current medications, also will be compiled.  Particular attention will be focused on the appearance of the skin and the physician will check for presence of stridor, a crowing sound during inhalation that may indicate angioedema in the throat. Stridor requires immediate medical treatment.

An allergy skin test may be recommended to pinpoint allergens that may be triggering angioedema. During this procedure, a tiny dose of an allergen is introduced to the skin. If the skin reacts with a wheal (raised, red bump), it indicates an allergic response to the allergen.

In some cases, an allergy blood test – such as a RAST (radioallergosorbent test) – may be used to diagnose an allergy. This type of blood test allows a laboratory to directly test a blood sample for antibodies that correspond to specific allergens. Though less sensitive than a skin test, it can be used on individuals who are taking antihistamines (drugs that can suppress or interfere with skin test results), or have reactions too severe for a skin test.

Blood tests can measure C1 inhibitor levels and activity to establish whether or not the patient has hereditary angioedema. A patient’s family medical history is useful in this diagnosis, as well, because of the inherited nature of the disorder. In some cases, genetic testing and counseling may be advised for prospective parents who have a family history of hereditary angioedema.