Allergies, Medicines, Genes and Unknown Triggers
Angioedema has several causes, which fall into two main groups: swelling driven by histamine, and swelling driven by bradykinin. Identifying which group applies determines treatment.
Histamine-Mediated Causes
- Food allergy (nuts, shellfish, eggs, milk)
- Medication allergy (penicillins, NSAIDs)
- Insect stings
- Latex
- Chronic spontaneous urticaria
Bradykinin-Mediated Causes
- ACE inhibitors, a common class of blood pressure medicines
- Hereditary angioedema
- Acquired C1 inhibitor deficiency, sometimes linked to other diseases
Other Triggers
Infections, physical stimuli such as cold or pressure, and hormonal changes can also be involved. In many people, no cause is found, which is called idiopathic angioedema.
How a Doctor Finds the Cause
Your doctor will review medicines, foods, family history and other symptoms. Tests such as C4 and C1 inhibitor levels are used when hives are absent. Read about general hives causes.
When to Call 911
Call 911 right away if hives or swelling occur with difficulty breathing or swallowing, a tight or closing throat, a swollen tongue, lips or face, wheezing, faintness, or a sudden feeling of impending doom. Use an epinephrine auto-injector first if one has been prescribed to you, then call for emergency help.
When to See a Doctor
See a doctor if your symptoms last more than a few days, keep coming back, cover large areas, or interfere with sleep or daily life. Dr. Tiffany Young founded the Hives Treatment Center in San Francisco, a practice focused on diagnosing and treating angioedema.
Frequently Asked Questions About Angioedema Causes
Can stress cause angioedema?
It may trigger attacks in some people, particularly with HAE.
Can angioedema be caused by blood pressure medicine?
Yes, ACE inhibitors are a well-known cause.
Is angioedema always an allergy?
No. Many forms are not allergic.
Get Relief for Your Hives
Find the cause, and you can usually prevent future episodes. Visit our hives treatment page to see the latest treatment options for your outbreak.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis or treatment. If you think you are having a medical emergency, call 911.
