When is a fever too high?
Last updated September 3, 2026.
Adults: call the doctor at 103 F, at 3 days of any fever, or sooner with severe headache, stiff neck, confusion, chest pain, breathing trouble, vomiting, or rash. ER: 105 F, or fever with confusion, seizure, stiff neck, or a non-blanching purple rash. Context matters: fever is defense, most infection fevers stay under 105 F, and behavior beats the number; a coherent 103 F adult is safer than a confused 101 F one. Kids differ: 100.4 F under 3 months old is always a same-day call. Lower thresholds apply to the immunocompromised, pregnant women, recent surgery patients, and the elderly, who can be dangerously ill with confusion and little fever. Home care while monitoring: aggressive fluids, light clothing, acetaminophen or ibuprofen for comfort, and temperature checks every few hours, not every few minutes. Recurring fevers over weeks are a workup, not a wait-and-see.
What to do
- Adults: 103 F or 3 days means call the doctor.
- 105 F, confusion, stiff neck, purple rash: ER.
- Baby under 3 months at 100.4 F: same-day call.
- Immunocompromised or pregnant: lower the bar.
- Treat misery, not the number: fluids, light clothing, acetaminophen.
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