Angioedema is swelling of areas of tissue under the skin, sometimes affecting the face and throat.
Angioedema can be a reaction to a drug or substance (trigger), a hereditary disorder, a rare complication of cancer, or an immune disorder, but sometimes the cause is not known.
Angioedema may involve swelling in the face, throat, digestive tract, and airways.
Antihistamines can relieve mild symptoms, but if angioedema makes swallowing or breathing difficult, prompt emergency treatment is needed.
Angioedema often occurs with hives. Both hives and angioedema involve swelling, but in angioedema, the swelling is deeper (under the skin) than it is with hives, and it may not itch.