Angioedema: Causes, Emergency Warning Signs, and Why Treatment Depends on the Type
Angioedema is swelling in deeper layers of the skin or mucous membranes. It commonly affects the lips, eyelids, face, tongue, hands, feet or genitals. Swelling involving the tongue or throat can threaten the airway.
Not all angioedema is the same
Angioedema can be caused by different mechanisms, and treatment depends on the cause.
- Histamine-mediated angioedema often occurs with hives or an allergic reaction.
- ACE-inhibitor angioedema can occur in people taking blood-pressure medicines whose generic names often end in “-pril.” It may occur even after years on the medicine.
- Hereditary angioedema (HAE) is a rare genetic disorder involving the bradykinin pathway, often related to C1 inhibitor dysfunction.
- Acquired or spontaneous angioedema has other possible causes and may require specialist evaluation.
Emergency warning signs
Tongue or throat swelling, trouble breathing, difficulty swallowing, voice change, fainting, or signs of anaphylaxis require emergency medical care.
Why antihistamines do not work for every type
Antihistamines can help histamine-mediated swelling. Epinephrine is essential when angioedema is part of anaphylaxis.
However, hereditary angioedema and ACE-inhibitor angioedema are generally bradykinin-mediated. Antihistamines, corticosteroids and epinephrine do not reliably treat HAE itself; targeted therapies are available once the diagnosis is established.
Diagnosis
The pattern of swelling, presence or absence of hives, medication history, family history and triggers guide the evaluation. Recurrent swelling without hives may lead to testing of C4 and C1 inhibitor levels or function.
Medication-related swelling
If angioedema may be related to an ACE inhibitor, seek medical advice promptly. Do not restart or change prescription medication on your own after a serious reaction.
Related guide
For severe allergic reactions, see Anaphylaxis: Symptoms, Epinephrine, and What to Do in an Emergency.
Editorial source
This article provides general education and does not replace emergency care or specialist allergy/immunology assessment.
