defervescence

Defervescence is the subsidence of fever, the process by which a raised body temperature returns toward normal and fever-related symptoms abate. Clinically, it denotes a transition in the course of an illness accompanied by fever. The term derives from Latin defervescere, meaning to grow cool.

Defervescence can occur spontaneously as the host clears an infection, or after interventions such as antipyretic drugs (for example acetaminophen or ibuprofen) or effective antimicrobial therapy that reduce pyrogenic stimuli.

Physiologically, defervescence involves a reversal of the febrile response. As inflammatory mediators decline, the hypothalamic set point falls back to baseline, enabling heat loss through vasodilation and sweating. Core temperature declines and patients may feel chill initially before cooling completes.

Clinically, the onset of defervescence can signal therapeutic response, but it is not a definitive measure of cure. Relapse or continuing underlying disease may occur after fever abates. Ongoing assessment should consider hydration status, hemodynamics, and objective markers of infection or inflammation, especially if fever returns or persists after initial cooling.

Defervescence is distinguished from dysregulated temperature states and should be interpreted in the context of the overall clinical picture. In some diseases, fever patterns are chronic or relapsing, and defervescence may be temporary or followed by recurrence.