Which term refers to swelling caused by an allergic reaction?

• A. Angioedema
• B. Ecchymosis
• C. Hemorrhage
• D. Inflammation

Answer: (A)

The term that refers to swelling caused by an allergic reaction is angioedema. This condition is characterized by localized swelling of the deeper layers of the skin, often associated with allergic responses. Angioedema typically occurs when the body releases histamines and other chemicals in response to an allergen, leading to an increased permeability of blood vessels. This results in fluid leakage into the surrounding tissues, causing the swelling commonly seen in areas such as the face, lips, and throat.

In contrast, ecchymosis refers to a bruise or discoloration of the skin due to bleeding under the skin, usually from trauma or injury, rather than an allergic response. Hemorrhage denotes significant blood loss from vessels, either externally or internally, and is not specifically linked to allergic reactions. Inflammation, while it does imply swelling, is a broader term that encompasses various responses by the immune system and is not limited to allergic reactions. It can occur due to infections, injuries, or autoimmune diseases. Therefore, angioedema is the most precise term for the specific swelling that arises from an allergic reaction.