When diagnosing angioedema without urticaria, patient’s history is very important. Checking which parts of the body are affected, the duration of bumps, the presence of similar family history, the drugs they take, and the presence of other medical conditions.

Laboratory testing for C1 inhibitor (C1-INH) is warranted, both qualitatively and quantitatively. In hereditary and acquired angioedema, this marker will probably show abnormality. A simpler, cheaper and indirect form of checking this – since this test may not be easily available – is to measure C4 (complement component 4), the levels of which will be abnormal in case of problems with the C1 inhibitor (C1-INH). If C4 levels are abnormal, C1 inhibitor measurement can be made in a specialized center.

These tests may present countless variations of potential results. Your doctor is qualified to interpret them and will determine whether to repeat and/or request other additional tests, or, also, repeat the tests during flares.

In the case of angioedema caused by ACE inhibitor, the result of these tests will be normal and there will be reports of ingestion of the drug causing the disease.

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