Angioedema refers to swelling of the deeper layers of the skin. This is due to accumulation of fluids caused by an allergic reaction. Angioedema most commonly affects the face, lips, eyes, hands, genitals and feet.
Causes and pathogenesis
Since this is an allergic condition, it is more often than not associated with exposure to a trigger or allergen.
Most people with angioedema may also have other allergic manifestations including hives or urticaria. Hives or urticaria are red and itchy rashes with welts and typical rash that appear over the skin.
Types of angioedema
Angioedema may classified into four basic types according to its cause:-
Angioedema caused due to allergies – this type of angioedema may be caused due to a food allergy or allergy to a food additive or color. This type of angioedema may occur along with an anaphylactic reaction.
Angioedema due to drugs – some drugs may also cause allergies leading to angioedema. One of the common examples includes high blood pressure medications like angiotensin-converting enzyme (ACE) inhibitors, hormonal contraceptives, pain relievers like non steroidal anti-inflammatory drugs (NSAIDs like aspirin, ibuprofen etc.). Angiedema with the use of medications occurs as a side effect.
Genetic causes of angioedema
Idiopathic angioedema when no cause can be identified.
The swelling is pale and non-itchy. Symptoms last for 1 or 2 days. If angioedema affecting the tongue or upper airway is rapid, there may be difficulty in breathing. This can be life-threatening.
If the condition affects the gastrointestinal tract, there may be severe pain that is often mistaken for appendicitis, diverticulitis or mesenteric ischemia.
The swelling is caused by an increase in capillary leakage. There is leakage of fluids from the smaller blood vessels called capillaries. This leakage occurs due to release of mediators and chemicals of inflammation.
Who suffers from angioedema?
Angioedema is quite a common condition. It may affect up to 10-20% of the population in their life time.
Allergies to foods and medications are the most common type of angioedema. Food related allergies for example affect about 5-8% of children and 1-2% of adults.
Similarly angioedema due to ACE inhibitors affect around 1-5% of people who take them.
Idiopathic angioedema that may be long lasting or chronic may affect 1 in 2,000 persons.
Hereditary angioedema affects between 1 in 10,000 and 1 in 50,000 people worldwide and is thus considered rare.
Diagnosis of angioedema
Diagnosing angioedema is mainly with the help of history of exposure to a trigger and presentation with typical clinical features.
Idiopathic angioedema is typically diagnosed when no known cause or exposure is found.
Treatment of angioedema
Angioedema usually gets better without treatment after a few days if the trigger or allergen is removed.
Anti-allergy medications like antihistamines and steroids can be used to relieve the swelling and hasten recovery. Drug-induced angioedema needs use of alternative medications.