What should you know about subjective fever?

Body temperature changes, warm surroundings, exercise, hormonal shifts, dehydration, anxiety and some medicines can make you feel feverish. Infection can also cause the sensation, including a common cold, acute bronchitis, COVID-19, chickenpox, cellulitis, croup or other illnesses. Feeling feverish alone cannot identify the cause. Use a reliable thermometer as directed and note the reading, time, chills, sweating, pain, cough, rash or other symptoms.

Rest, drink fluids and wear light clothing while you monitor symptoms. Avoid extreme cooling methods. Follow the label or a clinician's advice if you use a fever-relieving medicine, and check that another product does not contain the same ingredient. Stay away from vulnerable people if you may have an infectious illness and follow local testing or isolation advice when relevant. Arrange medical advice if the sensation persists, a measured temperature rises, or symptoms are worsening.

Seek urgent help for difficulty breathing, confusion, fainting, a stiff neck, a seizure, a rapidly spreading rash, severe dehydration or severe pain. A baby, older adult, pregnant person or someone with reduced immunity may need earlier assessment for infection. Prompt medical advice is also appropriate when feverishness follows heat exposure, continues with marked weakness, or occurs with a concerning new symptom.

Ask whether your thermometer and measurement method are reliable, which symptoms suggest infection, how long to monitor, and which medicines are safe with your conditions. Mention travel, sick contacts, new medicines and any immune or pregnancy considerations.