Chills

Chills are sudden feelings of cold, sometimes with shivering, goosebumps, or chattering teeth. They can happen in a cold place, but they also commonly occur as your body develops a fever.

During a fever, the brain temporarily raises the body’s temperature target. Although your temperature may be rising, you can feel cold. Your muscles contract quickly to create heat, causing shivering. Very strong shaking chills are sometimes called rigors.

Chills are a symptom, not a disease. Their strength does not always show how serious the cause is.

You may suddenly want extra clothing or blankets even though the room feels comfortable to others. Your arms, legs, jaw, or whole body may shake, and your skin may look pale or develop goosebumps.

With an infection, you may also have fever, sweating, headache, muscle aches, cough, sore throat, nausea, diarrhea, or tiredness. Chills sometimes happen before a thermometer shows a high temperature.

Chills can also occur without fever, such as after cold exposure, during intense anxiety, or with some medication reactions. Shaking caused by low blood sugar, tremor, or another condition may feel similar but is not always true chills.

If possible, check your temperature with a thermometer. Note when the chills started and what other symptoms are present.

Common causes include respiratory viruses, such as influenza or COVID-19, and other short-term viral illnesses. Stomach and intestinal infections can also cause chills, often with vomiting or diarrhea.

Bacterial infections may affect the urinary tract, kidneys, lungs, skin, teeth, or throat. Symptoms such as painful urination, side or back pain, a worsening cough, or red and painful skin may help identify the source.

Cold or wet surroundings are another common cause. Shivering is the body’s normal attempt to produce heat.

Less common causes include reactions to medicines, vaccines, blood transfusions, or intravenous treatments. Hormonal changes and intense emotional reactions can sometimes cause cold sensations or shaking. Repeated chills may occasionally be related to a longer-lasting infection or inflammatory condition.

Urgent causes include sepsis, a dangerous whole-body response to infection. Chills may also accompany meningitis, severe pneumonia, a kidney infection, or hypothermia. These conditions cause other warning signs; chills alone do not mean you have one.

Call emergency services now if chills occur with:

• Severe difficulty breathing, blue or gray lips, or chest pressure
• New confusion, fainting, a seizure, or difficulty waking
• A stiff neck with a severe headache or a rapidly spreading rash
• Signs of severe cold exposure, such as slurred speech or poor coordination
• A temperature below 35°C or 95°F after cold exposure

Arrange same-day medical care if you have chills with a fever and painful urination, side or back pain, a worsening cough, repeated vomiting, severe weakness, or a painful spreading skin infection.

Also seek prompt advice if you are pregnant or have a weakened immune system because of chemotherapy, a transplant, certain medicines, or an immune condition. Tell clinical staff immediately if chills begin during a transfusion or intravenous treatment.

For a baby younger than 3 months, a temperature of 38°C or 100.4°F or higher needs urgent medical assessment.

Book a routine appointment if chills continue for several days, keep returning without an obvious reason, or occur with ongoing night sweats, unexplained weight loss, or persistent tiredness.

A healthcare professional will ask when the chills began, whether you measured a fever, and what other symptoms you have. They may ask about recent infections, travel, cold exposure, new medicines, procedures, or contact with someone who was ill.

The examination may include checking your temperature, heart rate, breathing, blood pressure, throat, lungs, abdomen, skin, and hydration.

Tests are not always needed. Depending on your symptoms, they may include a nasal or throat swab, urine test, blood tests, or chest imaging. The purpose is to find the underlying cause.

Treatment depends on the cause. Viral illnesses often improve with time and supportive care. Bacterial infections may need antibiotics like amoxicillin or doxycycline, which do not treat viral infections.

While recovering at home:

• Rest and drink enough fluid to keep your urine pale
• Wear light, comfortable layers and adjust them as your temperature changes
• Replace wet clothing and move somewhere warm after cold exposure
• Avoid piling on heavy blankets if you have a high fever
• Do not use an ice bath, which can worsen shivering

Acetaminophen, also called paracetamol, or ibuprofen may reduce fever-related discomfort when used according to the label. These medicines are not suitable for everyone, so ask a pharmacist or healthcare professional if you are unsure. Do not give aspirin to a child or teenager unless specifically prescribed.

Chills caused by a brief viral illness may come and go over hours or a few days. An episode often settles once the body reaches its new temperature or the fever begins to fall.

Chills from cold exposure should improve as you become safely warm. Symptoms caused by another medical problem may continue or return until it is treated.

Keep track of repeated episodes, measured temperatures, and related symptoms. This information can help at an appointment.

Can you have chills without a fever?

Yes. Chills may happen before a fever appears or without any fever. Cold exposure, anxiety, and some medicine reactions can also cause them.

Are chills contagious?

Chills themselves are not contagious. However, the viral or bacterial infection causing them may spread to others.

Do strong shaking chills mean an infection is severe?

Not necessarily. Rigors can occur with several infections, and their intensity alone cannot show how serious the illness is. Repeated rigors with worsening illness, breathing problems, confusion, or severe weakness need prompt assessment.

Should I bundle up when I have chills?

Use enough clothing or bedding to feel comfortable, but avoid overheating. Light layers are easier to remove if the chills give way to sweating.

Why do chills sometimes come before sweating?

As a fever rises, you may shiver because your body is trying to reach a higher temperature. When the brain lowers that target again, you may feel hot and begin to sweat.