Chills for no obvious reason: what to know

Chills are involuntary muscle activity that helps generate heat. They can occur before, during or after a fever, but a normal temperature at one moment does not exclude an illness. Consider whether the episode followed cold exposure, poor sleep, anxiety, strenuous activity or a new medicine. Note associated symptoms such as cough, burning urination, back pain, rash, headache, diarrhoea or unusual weakness.

Different infections can present with chills. Influenza may bring respiratory symptoms and body aches; a Kidney Infection or Urinary Tract Infection may cause urinary changes or pain in the side. Pneumonia can affect breathing, while Malaria or Dengue Fever require consideration after relevant travel or mosquito exposure. Sepsis is a medical emergency involving a severe response to infection.

Measure your temperature during an episode and write down its timing, duration and accompanying symptoms. Move to a comfortable environment, use light layers and drink fluids if you can. Avoid overheating yourself with very hot baths or many heavy blankets. Arrange a clinical review if chills recur, last longer than expected, or occur with a new symptom, particularly after travel or a recent procedure.

Get urgent medical help for trouble breathing, chest pain, fainting, new confusion, severe weakness, a stiff neck, a rapidly spreading rash, or blue or grey lips. Seek prompt assessment for repeated shaking chills with fever, very little urine, severe pain, or a feeling that something is seriously wrong. Do not wait for a home temperature reading if you are deteriorating quickly.

Tell the clinician when the chills began, how episodes feel, your temperature readings, recent travel, insect bites, medication changes and any urinary, breathing or digestive symptoms. Ask whether you need an examination or tests and which changes should trigger urgent help.