What should you know about internal chills?

Chills happen when the body changes heat production or the nervous system responds to illness, stress or the surrounding temperature. Infection-related chills may occur before a measured fever and can accompany headache, muscle aches, cough, sore throat, urinary symptoms or pain in the back. Influenza and pneumonia can cause chills with respiratory symptoms. A kidney infection or urinary tract infection may add burning urine, frequent urination or flank pain. In areas where mosquito-borne illnesses occur, malaria or dengue fever can also cause feverish episodes. Chills are a symptom, not a diagnosis.

Check your temperature with a thermometer and record the time, readings and other symptoms. Rest, drink fluids if you can, and use light layers so you can adjust your comfort without overheating. Consider recent travel, sick contacts, urinary symptoms, cough, rash or new medicines when describing the episode. Do not start leftover antibiotics. A clinician can decide whether examination or testing is needed, particularly when chills recur or continue.

Seek emergency help for confusion, fainting, severe breathing difficulty, blue lips, a mottled appearance, extreme weakness or inability to keep fluids down. Chills with rapidly worsening illness, severe pain, very little urine or unusual drowsiness can be warning signs of sepsis. Obtain prompt medical advice for persistent fever, chills after travel, a new rash, chest symptoms or pain when passing urine.

Could an infection explain these episodes? Should I test my temperature at set times? Do my travel history or medicines change the assessment? Which changes require emergency care?