What happens if you leave a child’s high fever untreated?

Short answer: A child does not always need medicine just because they have a fever. With common infections, medicine is mainly for discomfort. The important questions are the child’s age, hydration, behavior and the illness causing the fever. Not giving fever medicine is different from delaying necessary medical care.

Does an untreated fever keep rising?

Ordinary infection-related fever does not usually keep climbing without a limit or cause brain damage. Heatstroke from environmental overheating is a different emergency. A lower temperature after medicine also does not prove that an illness is harmless. Seattle Children’s explains these fever myths.

When does a child with fever need care?

• Under 3 months: A temperature of 100.4°F (38°C) or higher needs immediate medical advice and prompt evaluation. Do not delay care to try fever medicine.
• Call the pediatrician promptly for repeated temperatures above 104°F (40°C), worsening illness, immune-system problems, or fever lasting over 24 hours under age 2 or over 3 days at age 2 and older.
• Call 911 for severe breathing difficulty, inability to wake, or purple/blood-colored spots with fever. Seek emergency care for confusion, a stiff neck or a seizure.

See the AAP’s when-to-call guidance and fever symptom checker. Follow your child’s own care plan if they have a medical condition.

Can fever medicine prevent febrile seizures?

No. Acetaminophen and ibuprofen do not prevent febrile seizures. These can occur even with a mild fever and usually affect children between 6 months and 5 years. Most are brief; a seizure lasting 5 minutes needs emergency help. See AAP febrile seizure guidance.

How can parents keep a child comfortable?

• Offer age-appropriate fluids; young babies need breast milk or formula. Watch for fewer wet diapers, a dry mouth or difficulty drinking.
• Use light clothing and allow rest. Avoid ice baths and alcohol rubs.
• If medicine is appropriate, use the child’s weight and product instructions. Ask a clinician before giving medicine under 3 months. Do not use ibuprofen under 6 months or aspirin unless a clinician specifically directs it.

MedlinePlus: caring for a baby with fever.

Related fever guides

Read when to worry about fever and home care and recurrent fever syndromes. This article provides general education; your child’s clinician can assess the cause and recommend care.