Overview

Angioedema is a condition characterized by sudden swelling beneath the skin or mucous membranes, often affecting the face, lips, tongue, throat, hands, and feet. This swelling occurs due to fluid accumulation in the deeper layers of the skin, typically resulting from an allergic reaction or other immune response. Angioedema can be acute or chronic, with some cases resolving quickly and others recurring over time. While mild episodes can be uncomfortable, severe cases—especially those involving the throat—can be life-threatening and require immediate medical attention.

Causes

Angioedema can develop due to various triggers, and the underlying cause often determines the type of angioedema:

• Allergic angioedema: Triggered by allergic reactions to foods (such as nuts, shellfish, eggs), insect stings, medications (like penicillin), or latex.
• Drug-induced angioedema: Commonly associated with certain medications, especially angiotensin-converting enzyme (ACE) inhibitors used to treat high blood pressure.
• Hereditary angioedema (HAE): A rare genetic condition caused by a deficiency or dysfunction of C1 inhibitor protein, leading to recurrent episodes of swelling without an allergic trigger.
• Idiopathic angioedema: Occurs without a known cause and may be recurrent or chronic.
• Acquired angioedema: Linked to underlying diseases such as autoimmune conditions, lymphoproliferative disorders, or certain infections.

Symptoms

The hallmark symptom of angioedema is rapid swelling beneath the skin or mucosa. Key features include:

• Swelling: Sudden, often painless swelling of the face, lips, tongue, throat, hands, feet, or genitals.
• Redness or warmth: The affected area may appear red and feel warm to the touch.
• Discomfort or tightness: Swelling can cause a sensation of fullness, tightness, or pain, especially in the face and throat.
• Difficulty breathing or swallowing: When the throat or tongue is affected, it can lead to airway obstruction and breathing difficulty, which is a medical emergency.
• Abdominal pain: In hereditary angioedema, gastrointestinal swelling can cause cramping, nausea, vomiting, and diarrhea.
• No itching: Unlike typical allergic reactions, angioedema often occurs without itching, though it may coexist with hives (urticaria).

Diagnosis

Diagnosis of angioedema involves clinical evaluation, medical history, and sometimes specific laboratory tests:

• Physical examination: A doctor examines the swelling pattern and checks for associated symptoms like hives or breathing difficulty.
• Medical history: Includes assessment of recent food intake, medication use, insect stings, or family history of angioedema.
• Blood tests: In suspected hereditary angioedema, blood tests can measure C4 complement levels and C1 inhibitor function.
• Allergy testing: Skin prick or blood tests may be done to identify possible allergens in allergic angioedema.
• Exclusion of other causes: For idiopathic or recurrent angioedema, autoimmune screenings or investigations for underlying conditions may be performed.

Treatment

Treatment of angioedema focuses on relieving symptoms, managing the underlying cause, and preventing recurrence:

• Mild allergic angioedema:
  • Antihistamines to reduce swelling and allergic response.
  • Corticosteroids in more severe or persistent cases to reduce inflammation.
• Severe or life-threatening cases:
  • Epinephrine injection (adrenaline) in cases involving airway compromise or anaphylaxis.
  • Emergency medical care with oxygen, intravenous fluids, and close monitoring.
• Hereditary angioedema:
  • C1 inhibitor concentrate (intravenous) during acute attacks.
  • Medications such as icatibant (bradykinin receptor antagonist) or ecallantide (kallikrein inhibitor).
  • Long-term prophylactic treatments like androgens (danazol) or C1 inhibitor replacement therapy to prevent attacks.
• Drug-induced angioedema: Discontinuation of the offending drug, particularly ACE inhibitors, is essential.
• Idiopathic angioedema: Managed with long-term antihistamines and sometimes low-dose corticosteroids if needed.

Prognosis

The prognosis of angioedema depends on the cause and severity. Most cases of allergic or drug-induced angioedema resolve within hours to a few days with appropriate treatment. Hereditary angioedema requires lifelong management but can be controlled with preventive medications and prompt treatment during attacks.

With proper medical care and avoidance of known triggers, many people with angioedema lead normal, healthy lives. However, it is crucial to seek immediate medical attention during any episode that affects breathing or swallowing, as untreated severe angioedema can be life-threatening.