What counts as a fever in adults?
A temperature of about 100.4°F (38°C) or higher is generally considered a fever. Normal body temperature varies by person, time of day, and measurement site, so a number slightly above your own baseline isn’t necessarily a fever — see what’s a normal body temperature.When is an adult fever an emergency?
The number matters less than the company it keeps. Get urgent care for a fever paired with a stiff neck, confusion, severe headache, difficulty breathing, chest pain, a new rash that doesn’t fade under pressure, or persistent vomiting. A very high fever (around 103°F/39.4°C or above) that won’t come down, or any fever lasting more than a few days, also deserves a call.Does a higher fever mean a worse illness?
Not reliably. The height of a fever doesn’t track neatly with how serious an illness is — a mild virus can spike a high number, and a serious infection sometimes causes only a modest rise. How you feel and your other symptoms are better guides than the thermometer alone.Who should be more cautious?
Older adults, people who are pregnant, and those who are immunocompromised or managing a chronic illness should have a lower threshold for seeking care, since fevers can signal more in these groups — and older adults sometimes run a blunted fever response. When unsure, check with a clinician.How do I track a fever at home?
Use a consistent method and time, and log the readings along with symptoms. A fast, reliable thermometer such as SonoHealth’s ThermoPRO makes repeat checks easy, and a clear record helps your doctor judge the trend. Rest, fluids, and over-the-counter fever reducers (used as directed) help comfort while you monitor.Related: Fever Guide · How to Take an Accurate Temperature · Low Body Temperature · Fever in Children Guide