Medical Term for Feeling Cold During Illness
The medical term for feeling cold during illness is "chills" or "rigors," which are common constitutional symptoms associated with fever and acute infections, particularly influenza and other respiratory viral illnesses. 1
Clinical Definition and Context
Chills occur in approximately 70% of patients with uncomplicated influenza infection and represent a subjective sensation of coldness often accompanied by shivering, despite the presence of fever. 1
- Chills are listed as a distinct symptom in the clinical case definition of influenza-like illness, separate from fever itself 1
- This symptom typically occurs during the acute phase of illness, particularly within the first 24 hours of fever onset 1
- The sensation of feeling cold paradoxically occurs while body temperature is actually elevated, often ranging between 38°C and 40°C 1
Pathophysiologic Mechanism
The sensation of chills during illness results from the body's thermoregulatory response when the hypothalamic set point is raised during fever:
- As the body attempts to reach the new, higher temperature set point, peripheral vasoconstriction occurs, causing the skin to feel cold 1
- Shivering may accompany chills as the body generates heat through muscle activity to reach the elevated set point 1
- Clinical findings during this phase include "hot and moist skin, a flushed face, injected eyes and hyperaemic mucous membranes" despite the patient's subjective sensation of coldness 1
Associated Symptoms in Influenza-Like Illness
Chills typically occur alongside other constitutional symptoms:
- Fever (the paramount symptom, present in most cases) 1
- Myalgia affecting mainly the back and limbs (~53%) 1
- Malaise (~80%) 1
- Headache (~65%) 1
- Cough (~85%) 1
Important Clinical Distinction
It is critical to distinguish chills associated with fever during acute illness from true hypothermia (core body temperature below 35°C), which represents a completely different pathophysiologic state requiring different management. 1, 2
- Hypothermia results from actual heat loss and represents a medical emergency requiring active rewarming 1, 2
- Chills with fever indicate the body is actively raising its temperature, not losing heat 1
- Patients with serious infections may paradoxically be hypothermic or euthermic rather than febrile, particularly elderly patients or those on anti-inflammatory medications 1