A high grade fever is generally defined as a body temperature of 103°F (39.4°C) or higher in adults, and 104°F (40°C) or higher in children. Fever is a common symptom of an underlying infection or illness, and it occurs when the body’s immune system releases chemicals that raise the body’s temperature to help fight off the infection.
A high grade fever may cause symptoms such as sweating, chills, headache, body aches, and fatigue. In some cases, a high fever can lead to complications, such as dehydration, seizures, or confusion. It is important to seek medical attention if a high fever lasts for more than a few days, is accompanied by other symptoms such as severe headache, stiff neck, or difficulty breathing, or occurs in infants or young children.