What should you know about sudden cold chills?

Chills are an involuntary feeling of cold with shivering or trembling. They may happen as a fever is rising, even before a thermometer shows a high temperature. Infections such as influenza, pneumonia, urinary tract infection, kidney infection, malaria, or dengue fever can present with chills alongside other symptoms. The pattern matters: cough, breathlessness, burning urine, flank pain, rash, recent travel, or repeated vomiting changes the level of concern.

Move to a comfortable room, use light layers, drink fluids if you can, and check your temperature with a thermometer. Note when the chills began and whether fever, cough, pain, diarrhoea, rash, or urinary symptoms follow. Do not take leftover antibiotics. Contact a clinician if chills keep returning, last beyond a brief episode, or occur with a suspected infection, recent travel, pregnancy, or a weakened immune system.

Seek emergency help for confusion, fainting, severe breathing difficulty, blue or grey lips, a seizure, severe weakness, or rapidly worsening illness. Urgent assessment is also needed for chills with a stiff neck, severe abdominal or flank pain, a widespread rash, or inability to keep fluids down. Sepsis can develop from infection and requires immediate treatment when a person becomes suddenly very unwell.

Could an infection explain my chills? Which temperature or symptoms should prompt urgent help? Do I need urine, blood, or other tests based on my travel and symptoms?