Angioedema diagnosis more often than not depends on the history of recent exposure to a triggering agent and presentation with typical clinical symptoms.
There are some tests that may be prescribed to determine the type of angioedema according to cause.
Diagnosis based on symptoms
Diagnosis is based on the symptoms of angioedema. Symptoms of angioedema include:-
Swelling of the skin. Angioedema commonly affects the face, eyes, lips, genitalia, hands and feet. The swelling is caused by a collection of fluid in the deep layers of the skin. In some cases the throat and the gastrointestinal tract may also be involved.
The swelling is acute or sudden in onset and is more aggressively progressing and severe than nettle rash or hives. It commonly lasts one to three days. There is usually no itching but a slight prickling sensation.
The swollen areas may feel hot and inflamed.
If there is rapidly growing swelling inside the throat and the tongue, breathing may become difficult and the condition may become life-threatening requiring urgent medical attention.
Eye swelling and swelling of the conjunctive may affect vision significantly.
Those with genetic or hereditary angioedema may also have nausea, vomiting, diarrhea and abdominal pain.
If the genitalia and urinary tract is involved, there may be pain and difficulty in passing urine.
Diagnosis of different types of angioedema
The diagnosis of each type of angioedema according to its cause includes:-
Diagnosing allergic angioedema
The first step in diagnosing an allergy is a detailed history of an exposure to a possible allergen or triggering agent. This could be foods like nuts, eggs, soy, shellfish etc. This could also be exposure to latex or other allergy triggering agents.
Physical triggers like cold, exercise, heat, sweating, sun (or light) exposure, pressure are also enquired. There could be a history of exposure to infections such as respiratory virus, viral hepatitis, or infectious mononucleosis. Exposures to irritants are work environments and recent insect sting or bite is asked.
Those who have an existing allergic disease for example hives or asthma are more likely to be affected. Exposure to medications also needs to be detailed in history while diagnosing allergic angioedema.
Further tests include the skin prick test and blood tests. These are usually performed at an allergy or immunology clinic. The skin prick test involves tiny pricks to the skin with very small amount of the suspected allergen. If allergic the results show up as inflammatory red and raised reactions at the specific pricks. Blood tests check for inflammatory markers in blood.
Diagnosing drug induced angioedema
Diagnosing this type of angioedema involves taking a detailed history of all the drugs consumed. This includes prescription, over-the-counter, alternative and herbal medicines as well. If withdrawal of the drug resolves the angioedema, the diagnosis of drug-induced angioedema is confirmed.
Diagnosing genetic angioedema
This form of angioedema is commonly inherited. There is a positive history of someone in the family (parent, sibling or a blood relation from either parent’s side) who has this condition. Blood is checked for level of proteins that are regulated by the C1-INH gene. Low levels are indicative of genetic or hereditary angioedema.
Diagnosing idiopathic angioedema
Idiopathic angioedema is diagnosed and confirmed when no other cause is found.