What should you know about intermittent fever?

Fever can fluctuate as the immune system responds to an infection, and it may also change after fever medicine wears off. A respiratory illness such as a common cold or COVID-19 can cause fever alongside cough, sore throat, congestion, tiredness, or body aches. Acute bronchitis may bring a persistent cough, while bronchiolitis is mainly a concern in infants and young children with breathing symptoms.

The fever pattern alone cannot identify its cause. Other possibilities include skin infection, chickenpox, croup, or less common infections such as brucellosis. Note the measured temperature, the time of each episode, chills or sweating, medicines taken, recent travel, insect or animal contact, and any new symptoms. This record gives a clinician useful context.

Rest, drink fluids regularly, and wear light, comfortable clothing. Check your temperature with the same reliable thermometer and record the reading rather than judging fever by touch. Follow the label or a clinician’s instructions for any fever medicine, and check before giving medicine to a child, especially if the child is very young or has another health condition.

Avoid starting antibiotics without medical advice: they do not treat viral illnesses and an unsuitable medicine can cause harm. Arrange a clinical review if episodes keep returning, interfere with daily activities, or occur with a cough, rash, urinary symptoms, abdominal pain, or unexplained weight change.

Seek urgent medical help for trouble breathing, bluish lips, a seizure, severe confusion, fainting, a stiff neck, a severe headache, or a rapidly spreading rash. Get prompt advice if a baby is unusually sleepy, difficult to wake, feeding poorly, or has fewer wet nappies. Urgent assessment is also sensible when fever occurs in someone with a weakened immune system or a serious long-term condition.

Contact a clinician when fever repeatedly returns, does not settle, or is accompanied by dehydration, ongoing vomiting, marked weakness, or worsening pain. Take your temperature record and a list of medicines to the appointment.

Ask what causes fit your fever pattern and other symptoms, whether you need an examination or tests, how to monitor your temperature, which medicines are suitable for you, and which changes should trigger urgent review.