Which of the following is classified as a sign?

In healthcare, a sign is an objective indication of a medical condition that can be observed or measured by someone other than the patient. A rash fits this definition perfectly because it can be seen on the skin and assessed by healthcare professionals during examinations. The presence of a rash provides valuable information about potential underlying issues, such as infections, allergic reactions, or other dermatological conditions, and can guide further evaluation and treatment.

In contrast, fatigue, headache, and lightheadedness are symptoms that are subjective. They are experienced and reported by the patient but cannot be directly observed or measured by a healthcare provider. While they are important for understanding a patient's condition and can indicate various health issues, they do not qualify as signs in the clinical assessment.