Fever

Find the first group that matches. Each one is a MySymptom care level, from most to least urgent.

1. Go to the ER now

   • Any fever of 100.4°F (38°C) or higher in a baby under 3 months old
   • Fever with a stiff neck, a severe headache, confusion, or a rash that does not fade when pressed
   • Fever with signs of sepsis: confusion, fast breathing, cold or blotchy skin, or feeling very unwell

2. Get seen today

   • Fever with shaking chills or a racing heart
   • Fever in someone with a weak immune system, for example during chemotherapy
   • Fever after a recent surgery

3. Call your doctor today

   • A temperature of 103°F (39.4°C) or higher in an adult that does not come down
   • Fever lasting more than 3 days, or coming back after it seemed gone
   • Fever during pregnancy
   • Fever with painful urination, a severe sore throat or vomiting that does not stop

4. Care for it at home

   • A mild fever with a cold or flu in a healthy adult who is drinking fluids and can rest

A fever is often felt before it's measured: chills, shivering, body aches, fatigue, sweating, flushed skin, and difficulty concentrating are all common. Some people swing between feeling hot and cold as the body works to reset its internal thermostat. A reliable thermometer is the best way to confirm and track it.

A fever is the body's way of turning up the heat to make itself a less hospitable place for invading viruses or bacteria. Most adults can comfortably tolerate a fever up to about 102°F (38.9°C) for short periods, and the fever itself is rarely the problem, it's a sign that the immune system is doing its job. The real questions are what is causing the fever and how the rest of the body is coping.

For most people, a fever from a common viral illness like a cold or flu will resolve on its own within a few days with rest, fluids, and over-the-counter fever reducers if needed. The threshold for concern is lower in infants, older adults, pregnant people, and anyone with a weakened immune system. In those groups, a fever should be evaluated more readily.

• Viral infections

  Colds, flu, COVID-19, and other viruses are by far the most common cause of fever in adults. These usually resolve in a few days.

• Bacterial infections

  Strep throat, urinary tract infections, pneumonia, and skin infections can all produce fever and often need antibiotic treatment.

• Heat exhaustion

  Prolonged heat exposure or strenuous activity in hot weather can raise core temperature without an infection being present.

• Inflammatory or autoimmune conditions

  Ongoing inflammation from conditions like rheumatoid arthritis or inflammatory bowel disease can cause low-grade fevers.

• Medications and immunizations

  Some medications and most vaccines can cause a brief, mild fever as part of the immune response.

• Less common causes

  Persistent fever without an obvious source can occasionally signal more serious conditions and warrants medical evaluation if it lasts.

These steps are for mild symptoms with none of the warning signs above. Ask a pharmacist before taking any medicine.

• Rest and stay hydrated

  Sleep, fluids, and electrolyte drinks help the body manage the energy cost of fever. Aim to keep urine pale yellow.

• Dress lightly

  Avoid bundling up in heavy blankets, which can trap heat. Light clothing and a normal room temperature are better.

• Cool compresses

  A cool, damp cloth on the forehead, neck, or wrists can ease discomfort. Avoid ice baths, which can cause shivering and actually raise temperature.

• Fever reducers when needed

  Acetaminophen or ibuprofen used as directed can help you feel better. The goal is comfort, not bringing the temperature to exactly normal.

• Soft, simple foods

  Light meals, soups, and broths are easier to manage when appetite is low.