Having chills refers to feeling excessively cold, even when you are wearing warm clothing or are wrapped in blankets. When you have the chills, you may also be shivering or look pale.

Chills are often related to fever, an increase in body temperature above normal (98.6 degrees Fahrenheit). Fever is a sign of inflammation or infection in the body.

Part of your body’s response to infection is to create a fever by raising body temperature. Chills are caused by rapid contraction and relaxation of the muscles to increase body temperature. A fever can help to kill infectious pathogens or prevent their spread because most pathogens that cause infection survive best at a normal body temperature.

Chills and fever can be caused by fairly benign conditions, such as a cold, or by serious conditions, such as influenza, malaria or meningitis. Chills and fever are more common in children than adults because even minor illnesses produce a fever in children. Children also tend to get higher fevers than adults.

Exposure to cold temperatures and a low body temperature (hypothermia, a body temperature at or below 95 degrees) can also cause chills as muscles contract and relax to warm the body. Autoimmune and inflammatory disorders, as well as some cancers, can also cause a fever and chills.

Chills can be a symptom of a serious or life-threatening infection or hypothermia. Seek prompt medical care or talk with a medical professional about your symptoms if they persist more than two days or if they cause you concern.

Fever in infants and very young children can quickly become serious. Infants do not usually develop chills, but seek prompt medical care for a fever in a child less than one year old. Seek immediate medical care (call 911) if you, or someone you are with, have been exposed to cold temperatures or cold water or have other symptoms, such as lethargy, difficulty breathing, stiff neck, or confusion.

Symptoms
What other symptoms might occur with chills?
Chills are often a sign of fever, which can be caused by a wide variety of infections. Chills can also be caused by hypothermia and other conditions. Chills often occur with other symptoms, which vary depending on the underlying disease, disorder or condition.

Symptoms may occur along with chills
Symptoms that may occur with chills include:

Aches and pains

Cough

Diarrhea

Earache

Fever

General ill feeling

Hot, dry skin or sweating

Lethargy

Nausea

Rash

Sweating

Vomiting

Serious symptoms that might indicate a life-threatening condition
In some cases, chills may occur with other symptoms, and certain combinations of symptoms that might indicate a serious or life-threatening condition that should be immediately evaluated in an emergency setting. Seek immediate medical care (call 911) if you, or someone you are with, have any of these life-threatening symptoms:

Change in level of consciousness or alertness, such as passing out or unresponsiveness

Crying inconsolably

High fever (higher than 101 degrees Fahrenheit)

Pale or bluish coloration of the skin , lips or nails (cyanosis)

Persistent watery diarrhea, possibly with blood

Respiratory or breathing problems, such as shortness of breath, difficulty breathing, labored breathing, wheezing, not breathing, or choking

Seizure

Stiff neck, possibly with nausea, vomiting and confusion

Very bad headache

Causes
What causes chills?
Chills are caused by a wide variety of infectious diseases, some of which are common, such as the flu. In some cases, chills can be due to an inflammatory condition, such as an allergic reaction, or an autoimmune disease, such as lupus. Chills and fever can accompany certain cancers as well.

Chills may also be a symptom of a serious or life-threatening condition that should be immediately evaluated in an emergency setting, such as hypothermia, which is an abnormally low body temperature.

Common infectious causes of chills
Chills can be associated with many different types of infections, such as:

Appendicitis

Bacterial gastroenteritis (food poisoning) or viral gastroenteritis (“stomach flu”)

Bronchitis

Common cold

Diverticulitis (inflammation of an abnormal pocket in the colon)

Ear infection

Infectious mononucleosis

Influenza (flu)

Meningitis (infection or inflammation of the sac around the brain and spinal cord)

Pneumonia

Strep throat

Urinary tract infection, especially a kidney infection (pyelonephritis)

Other infectious causes of chills
Other infectious causes of chills include:

Abscess (collection of pus in the skin, brain, liver, kidney or other organ)

AIDS

Cellulitis (bacterial skin infection)

Chest infection

Endocarditis (inflammation and possibly infection of the lining inside the heart)

Kidney infection

Malaria

Pelvic inflammatory disease (PID)

Sepsis (life-threatening bacterial blood infection)

Septic or infectious arthritis

Sexually transmitted diseases (STDs)

Tuberculosis (serious infection affecting the lungs and other organs)

Inflammatory causes of chills
Chills can also be caused by inflammatory conditions including:

Allergic reaction

Blood transfusion reaction

Inflammatory bowel disease (includes Crohn’s disease and ulcerative colitis)

Systemic lupus erythematosus (disorder in which the body attacks its own healthy cells and tissues)

Malignant causes of chills
Chills can also be caused by malignant conditions including:

Leukemia

Lymphoma

Cancer

Questions for diagnosing the cause of chills
To diagnose the underlying cause of chills, your doctor or licensed health care practitioner will ask you questions about your symptoms. You can best help your health care practitioner in diagnosing the underlying cause of chills by providing complete answers to these questions:

How long have you had the chills?

Have you had a fever? If so, how high was the fever?

Have you been exposed to cold temperatures or cold water without proper protection or clothing?

What other symptoms do you have?

What are the potential complications of chills?
Chills are usually a sign of an infectious or inflammatory process. In some cases, chills can be associated with a serious or life-threatening condition, such as meningitis or hypothermia. It is important to contact your health care provider promptly when you experience chills. Once the underlying cause is diagnosed, following the treatment plan you and your health care provider design specifically for you can help reduce potential complications including:

Brain damage from an extremely high fever

Dehydration due to reduced fluid intake, fever, and increased sweating

Dehydration due to diarrhea or vomiting

Seizures

Shock, coma and organ failure