Dengue fever often begins with an abrupt onset of symptoms that can be mistaken for a severe flu. The most frequently encountered dengue fever symptoms include: High Fever: One of the hallmark symptoms, dengue fever typically starts with a sudden and high fever, often reaching 104°F (40°C). Severe Headache: Intense headaches, sometimes referred to as “dengue headaches,” can be incapacitating and are commonly experienced during the early stages of the illness. Joint and Muscle Pain: Severe joint and muscle pain, likened to aching bones, earn dengue fever its colloquial name, “breakbone fever.”