Fever in Adults

Welcome to this symptom guide about fever. Sorry to hear you have a fever! This guide is intended for adults who have an abnormally elevated temperature. Although we think of normal body temperature as 98.6 degrees F, body temperature varies -- and so does the definition of fever. Since body temperature rarely climbs above 99.9 degrees without a reason, this guide will consider a fever to be present when the body temperature is 100.0 F (38 degrees C) or higher. While temperatures between 98.6 and 99.9 degrees might be high for you, minor elevations in temperature are less likely to be a true indication of illness and are often within the range of normal variation. There are many causes of fever. This guide will cover some of the most common, but it is not exhaustive; rarer causes will not be covered.
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