Which of the following are signs of an allergic drug reaction?

The correct choice highlights symptoms that are classic indicators of an allergic drug reaction. Rash, itching, and swelling are all manifestations of the immune system's response to a substance it perceives as harmful.

When a person is exposed to an allergen, the body may produce histamines, which lead to common allergic symptoms. A rash is often associated with skin reactions such as hives, while itching can be a direct result of histamine release. Swelling, particularly in areas such as the face, lips, or tongue, is another common sign of an allergic response, which can also progress to more severe reactions, including anaphylaxis if not addressed promptly.

In contrast, the other choices include symptoms that are more typical of non-allergic side effects or unrelated health issues. For instance, nausea and sleepiness do not signify an allergy; instead, they are often side effects of various medications.