Fever in Adults: When Observation Is Enough—and When It Is Not

Fever is a symptom, not a diagnosis. Duration, associated symptoms and the person's overall condition matter more than the temperature alone.

Fever has many causes

Viral and bacterial infections are common, but fever can also occur with inflammatory disease, medicines and other conditions. The pattern alone rarely provides a definite diagnosis.

What to monitor

Note the duration, highest measured temperature, chills, rash, cough, urinary symptoms, abdominal symptoms, travel/exposure history and any new medicines. Hydration and overall alertness are important.

Avoid unnecessary antibiotics

Antibiotics do not treat viral infections and inappropriate use contributes to side effects and antimicrobial resistance. Testing and treatment depend on the clinical picture.

Seek medical care promptly

Urgent assessment is appropriate for confusion, severe breathlessness, persistent low blood pressure/fainting, stiff neck, seizure, severe dehydration, rapidly spreading rash, significant bleeding, pregnancy with concerning symptoms, or fever in an immunocompromised person.

Important: This page provides general health education and cannot diagnose an individual. New, severe or rapidly worsening symptoms need direct medical assessment.

Emergency symptoms: If there is severe chest pain, major breathing difficulty, new weakness/speech difficulty, loss of consciousness, seizure, severe bleeding or another rapidly life-threatening problem, seek emergency medical care rather than waiting for an online response.