What should you know about crimson fever?

Fever happens when the body's temperature control centre raises its set point, often as part of an immune response. Viral illnesses such as a common cold or COVID-19 can cause it, as can bacterial infections such as acute bronchitis, cellulitis, or brucellosis. Chickenpox and croup are other possible infectious causes. Fever alone cannot identify which condition is present, and some infections occur without fever.

Alongside fever, notice whether there is cough, sore throat, rash, breathing difficulty, pain, vomiting, diarrhoea, confusion, or unusual sleepiness. The pattern gives a clinician more useful information than the colour word used to describe the fever.

Rest, drink fluids regularly, and wear light clothing while avoiding overheating. Check your temperature with a reliable thermometer and record when it rises, how long it lasts, and any new symptoms. Use fever medicine only as directed on its label or by a clinician; check first if the person is a child, pregnant, elderly, dehydrated, or taking other medicines. Do not give aspirin to children.

Stay home from close contact when you feel unwell, especially if respiratory symptoms are present. A clinician may need to examine you, check hydration and breathing, and decide whether testing or treatment is appropriate.

Seek urgent help for trouble breathing, blue or grey lips, a seizure, severe headache with a stiff neck, confusion, collapse, severe dehydration, or a rapidly spreading rash. Babies and young children need prompt advice when fever is persistent, they are difficult to wake, feeding poorly, or producing fewer wet nappies. Contact a clinician when fever is worsening, keeps returning, lasts beyond a few days, or occurs in someone with a weakened immune system or serious long-term illness.

Ask: What causes should we consider with these symptoms? How should I measure and record the temperature? Which fever medicines are suitable with my other medicines? What changes mean I should seek urgent help?