Alternate Names : Rigors, Shivering
A chill is a sensation of cold. When chills occur at an unexpected time, they may be due to a fever-causing illness.
What is going on in the body?
Anyone can experience chills as a normal reaction, such as going out into the cold. In medical terms, chills usually refer to those that occur in an unexpected setting.
The brain closely regulates the body's normal temperature. When an infection occurs, infection-fighting cells in the body make certain chemicals. In some cases, these chemicals may travel through the bloodstream and cause the brain to raise the normal temperature inside the body. This is how a fever occurs. When the brain raises the temperature set point in the body, a person gets a feeling of cold. This feeling may stop if the new set point is reached. Shivering may even occur, as the body tries to use muscle movement to raise the temperature.
What are the causes and risks of the condition?
Chills have several causes, including:
menopause, which can cause chills as well as hot flashes and other symptoms
infections of any type, especially when bacteria get into the bloodstream. Common infections that cause chills include flu, strep throat, and pneumonia.
cancer, such as the blood cancers called leukemia and lymphoma
reactions to medications, such as antibiotics and antiseizure medications
autoimmune disorders, in which a person's immune system attacks his or her own body. An example is systemic lupus erythematosus, which can affect many areas of the body.
In some cases, the cause is unknown. Many elderly people feel cold at temperatures that younger people find normal. This is generally considered a normal effect of aging.