Angioedema and anaphylaxis are two different conditions, but they share many of the same triggers and symptoms.
Angioedema is swelling in the tissues underneath the skin. It’s marked by sudden changes in skin color, tingling, burning, tightness, and pain, but itch isn’t typically a symptom of angioedema.
Angioedema can, however, occur alongside other conditions that may cause itchiness, including anaphylaxis.
Learn the differences and similarities between angioedema and anaphylaxis, including potential causes and treatment options.
Angioedema and anaphylaxis are distinct medical conditions, though they do share many features, such as potential triggers and symptoms.
Anaphylaxis is a severe, systemic (affecting the entire body) allergic reaction. It can affect multiple organ systems, such as the skin, airways, and digestive tract. It’s a very serious condition and can be life threatening if not treated quickly.
Angioedema is a common manifestation of anaphylaxis and can be seen in up to 90% of cases. It often occurs alongside urticaria (hives), which feel itchy. Angioedema that occurs with anaphylaxis is often classified as histamine-mediated, meaning it’s caused by high levels of histamine.
Histamine-mediated angioedema accounts for about 40% to 70% of cases, but not all of these reactions are considered anaphylaxis. In many cases, histamine-mediated angioedema is self-limiting, meaning it doesn’t spread and cause other serious complications. In some cases, though — such as when the throat or airways are affected — it can also be severe and life threatening, even in the absence of anaphylaxis.
Different types of angioedema can have other causes, including certain medications, infections, genetics, or other underlying health conditions.
The possible triggers for histamine-mediated angioedema and anaphylaxis are similar and may include various types of foods, medications, and insect venoms.
Common food triggers for both angioedema and
- dairy
- eggs
- peanuts
- tree nuts
- sesame
- wheat
- shellfish
Medications that can cause anaphylaxis or angioedema
Among the medications that can cause anaphylaxis, antibiotics and nonsteroidal anti-inflammatory drugs (NSAIDs) are the most common triggers.
Beta-lactams are a class of antibiotics that includes medications that are particularly prone to causing anaphylaxis. Other types of medications — like immune-modulating drugs or chemotherapies — can also cause anaphylaxis in some people.
NSAIDs, along with another type of medication known as angiotensin-converting enzyme (ACE) inhibitors, can cause a type of nonallergic angioedema due to their effects on blood vessels within the body. This type of angioedema can still be serious, but it’s usually distinct from anaphylactic reactions.
| Antibiotics | NSAIDs | ACE inhibitors | Immune- modulating drugs | Chemotherapy | |
|---|---|---|---|---|---|
| Anaphylaxis | yes | yes | no | yes | yes |
| Angioedema | no | yes | yes | no | no |
Other possible causes of histamine-mediated angioedema include:
- cold or heat exposure
- physical activity
- UV radiation
- vibration
Epinephrine is a cornerstone treatment for anaphylaxis and may also be used to manage histamine-mediated angioedema.
Other types of medications that may be used for both histamine-mediated angioedema and anaphylaxis include steroids and antihistamines.
If the airways are affected, additional measures such as intubation or surgical intervention may be needed for either angioedema or anaphylaxis.
Because the treatments for histamine-mediated angioedema and anaphylaxis are the same, it’s often not necessary to identify the exact cause of symptoms before treatment starts. Once the person is stable, the healthcare team may ask about triggers or run blood tests to identify the cause.
Anaphylaxis can typically be differentiated from angioedema based on the extent of symptoms. In an anaphylactic reaction,
If angioedema is due to a nonallergic cause, additional bloodwork or genetic testing may be done to identify the cause of these symptoms.
Anaphylaxis is a severe and potentially life threatening allergic reaction. Angioedema often occurs alongside anaphylactic reactions, but there are many other potential causes of this condition that may be unrelated to allergies.
Regardless of the cause, it can also be very serious if swelling from angioedema occurs within the airways, and emergency intervention may be needed.
If you experience anaphylaxis or angioedema affecting the airways, seek immediate medical care. After treatment, it’s important to identify the cause of the reaction so you can avoid that trigger and prevent serious reactions in the future.
If doctors are unable to identify a nonallergic trigger for angioedema, you may need more tests. These can help work out whether medications, genetics, or underlying health conditions may be causing these symptoms.