Which of the following responses is a sign of a potential allergic reaction to penicillin?

A skin rash is a common and notable sign of a potential allergic reaction to penicillin. Allergic reactions can manifest in various ways, and skin rashes are particularly indicative of an immune response where the body identifies penicillin as a harmful substance. This can range from mild rashes to more severe reactions like urticaria (hives) or even anaphylaxis, which is a life-threatening condition. Recognizing a skin rash as a possible sign of an allergy is crucial for healthcare providers, as it helps them take timely actions to prevent further complications or introduce alternative treatments.

In contrast, while fever can sometimes occur with infections rather than as a direct sign of an allergic reaction, it is more often associated with the body’s response to an infection rather than an allergy. Headaches can be side effects of various medications but do not specifically indicate an allergic reaction to penicillin. Increased thirst is not typically associated with allergic reactions; rather, it may indicate dehydration or other conditions, thus it is less relevant in this context.