Which of the following is a sign or symptom of Malaria?

Fever alternating with chills is a hallmark sign of malaria. This pattern occurs due to the cyclical nature of the malaria parasite's life cycle within the human host. As the parasites invade red blood cells, they multiply and eventually cause the cells to burst, releasing more parasites into the bloodstream. This release triggers the immune response, leading to fever. The chills follow as the body attempts to regulate its temperature in response to the high fever. The intermittent nature of fever and chills is characteristic of malaria and helps distinguish it from other infections where fever may not alternate in this way.

In contrast, the other symptoms listed do not commonly characterize malaria. Persistent cough can be associated with respiratory infections, a skin rash is more indicative of various other dermatological conditions or drug reactions, and severe headaches may occur in several illness contexts but are not distinctive for malaria.