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.
Symptoms & Signs
What are the signs and symptoms of the condition?
When a person complains of chills, a healthcare provider may ask:
when they started
how often they occur
whether the person has noticed a fever or felt ill
whether the person has been around others that are sick
whether any other symptoms are present, such as nausea, weight loss, sore throat, or a rash
what other medical problems a person has, if any
what drugs, herbs, medications, or other therapies a person takes, if any
whether or not a woman may be going through menopause
Other questions, such as a person’s sexual practices, may also be asked in certain settings.
Diagnosis & Tests
How is the condition diagnosed?
Diagnosis of chills begins with a history and physical exam. This may be all that is needed. In other cases, further tests are ordered.
A complete blood count, or CBC, can help diagnose an infection or blood cancer. Blood hormone levels may be measured if menopause is suspected. If an autoimmune disorder is suspected, an antibody titer may be done. If a kidney infection is suspected, a urinalysis and urine culture may be done on a sample of urine.
Other tests may also be ordered in certain settings. For instance, a chest x-ray will be done if pneumonia is suspected.
Prevention & Expectations
What can be done to prevent the condition?
Prevention of chills is related to the cause, but is often not possible. Avoiding sick people and medications that can cause chills may help prevent some cases.
What are the long-term effects of the condition?
Chills themselves are temporary, and cause no long-term effects. Long-term effects are entirely related to the cause. For instance, those with the flu often get better and have no long-term effects. Pneumonia may go away with treatment, but can cause death in severe cases. Autoimmune disorders can cause damage to different areas of the body, such as the kidney, joints, and lungs.
What are the risks to others?
Chills are not contagious. However, if the chills are due to an infection, the infection may be contagious.
Treatment & Monitoring
What are the treatments for the condition?
Treatment for chills is directed at the cause. Acetaminophen or ibuprofen can be used to reduce a person’s fever. If a person has an infection, antibiotics may be advised. If a medication is the cause, it may need to be stopped.
Women going through menopause may want to discuss hormone replacement therapy options with the healthcare provider. This often consists of taking pills to replace the main female hormones, such as estrogen, that become low in menopause. A person with an autoimmune disorder may need medications to reduce inflammation or suppress the immune system. Someone with cancer may need surgery, chemotherapy, or radiation treatment.
What are the side effects of the treatments?
Side effects depend on the treatments used. For instance, ibuprofen can cause allergic reactions and stomach upset. Prednisone can cause weight gain, weakened bones, and mood swings. Hormone replacement therapy has many side effects, such as an increased risk of blood clots. Surgery carries a risk of infection, bleeding, and allergic reactions to anesthesia.
What happens after treatment for the condition?
Someone with the flu often gets better in a few days with or without treatment. A person with cancer or an autoimmune disorder may need treatment for life.
How is the condition monitored?
Any new or worsening symptoms should be reported to the healthcare provider. Other monitoring will depend on the cause. For instance, those with blood cancer may need repeated blood tests to follow the disease and the response to treatment.