Which side effect is specifically categorized as a hypersensitivity reaction?

Anaphylaxis is classified as a hypersensitivity reaction, specifically as a type I hypersensitivity response. This involves an immediate immune reaction that occurs when the immune system overreacts to a foreign substance, such as a drug or allergen, resulting in severe and potentially life-threatening symptoms. These can include swelling, difficulty breathing, rapid heartbeat, and a drastic drop in blood pressure.

In contrast, hoarseness, adrenal suppression, and headache do not fall under the category of hypersensitivity reactions. Hoarseness can result from various causes, including irritation or injury to the vocal cords. Adrenal suppression refers to a decrease in adrenal gland function, often associated with prolonged use of corticosteroids, and is not an immune response. Headaches can occur due to numerous factors, including tension or vascular changes, and are not related to an allergic reaction. Understanding the specific nature of anaphylaxis helps in recognizing the urgency of managing such reactions in clinical settings.