What Is a Fever?
A fever is a temporary increase in body temperature, often due to an illness. It's one of the body's natural defenses against infection—the elevated temperature helps fight off bacteria and viruses by creating a less favorable environment for them to thrive. While fevers can be alarming for parents, they're usually not dangerous in themselves and are a sign that the body's immune system is working properly.
A fever is generally defined as a body temperature above 100.4°F (38°C) when measured rectally, or above 99°F (37.2°C) when measured under the arm (axillary). Normal body temperature varies slightly depending on the time of day, activity level, and how the temperature is measured.
📌 Important Perspective: Fever is not an illness itself—it's a symptom. The height of the fever doesn't always indicate how sick your child is. A child with a mild illness can have a high fever, while a child with a serious illness might have a low or even no fever.
Understanding Temperature Ranges
✅ Normal Temperature
- • Rectal: 97.5°F - 100.3°F (36.4°C - 37.9°C)
- • Oral: 97.6°F - 99.6°F (36.4°C - 37.5°C)
- • Axillary (Armpit): 96.6°F - 98.6°F (35.9°C - 37.0°C)
- • Ear: 97.5°F - 100.4°F (36.4°C - 38°C)
⚠️ Low-Grade Fever
- • Rectal: 100.4°F - 101°F (38°C - 38.3°C)
- • Often manageable at home
- • Monitor for other symptoms
🌡️ Moderate Fever
- • Rectal: 101°F - 103°F (38.3°C - 39.4°C)
- • Common with many illnesses
- • Treat discomfort, ensure hydration
🔴 High Fever
- • Rectal: Above 103°F (39.4°C)
- • Contact doctor for guidance
- • More concerning in infants under 3 months
💡 Note: Rectal temperatures are most accurate for infants and young children. Different measurement methods give different readings—rectal is typically highest, then oral, then axillary.
Common Causes of Fever in Children
🦠 Viral Infections (Most Common)
- • Common cold and flu
- • Stomach viruses (gastroenteritis)
- • Roseola
- • Hand, foot, and mouth disease
- • COVID-19
- • Other respiratory viruses
🔬 Bacterial Infections
- • Ear infections
- • Strep throat
- • Urinary tract infections (UTIs)
- • Pneumonia
- • Sinus infections
- • Skin infections
💉 Immunizations
Low-grade fever for 1-2 days after vaccination is common and normal as the body builds immunity
🦷 Teething
May cause slight temperature elevation (usually under 100.4°F), but doesn't cause high fevers
🌡️ Overdressing/Overheating
Infants can develop elevated temperature from being too bundled up or in hot environments
🚨 When to Seek Medical Care
Call 911 or Go to ER Immediately If:
• Seizure with the fever
• Difficulty breathing or turning blue
• Stiff neck or severe headache
• Unresponsive or very difficult to wake
• Inconsolable crying for hours
• Purple/red rash that doesn't fade
Call Doctor Right Away If:
• Child is under 3 months with fever ≥100.4°F (38°C)
• Fever above 104°F (40°C)
• Fever lasts more than 3 days
• Signs of dehydration (no tears, dry mouth, no urine)
• Child appears very ill or listless
• Pain with urination
• Fever returns after being gone 24+ hours
• Weakened immune system (chronic illness)
Call Doctor During Office Hours If:
- • Child is 3-6 months old with fever above 101°F (38.3°C)
- • Fever comes and goes for more than a week
- • Child has chronic medical condition
- • You have concerns about your child's condition
How to Treat Fever at Home
The goal isn't necessarily to eliminate the fever completely, but to keep your child comfortable:
💊 Fever-Reducing Medications
Acetaminophen (Tylenol)
- • Safe for children 2 months and older
- • Dose based on weight (read label carefully)
- • Can give every 4-6 hours as needed
- • Don't exceed maximum daily dose
Ibuprofen (Advil, Motrin)
- • Safe for children 6 months and older
- • Dose based on weight (read label carefully)
- • Can give every 6-8 hours as needed
- • Give with food to prevent stomach upset
⚠️ Important Warnings:
- • Never give aspirin to children—can cause Reye's syndrome
- • Don't alternate medications without doctor's advice
- • Use only medications formulated for children
- • Use dosing device that comes with medication
- • Check all medications child is taking to avoid doubling up
💧 Hydration
- • Offer fluids frequently—water, breastmilk, formula
- • Popsicles and ice chips if child won't drink
- • Electrolyte solutions (Pedialyte) for dehydration risk
- • Avoid sugary drinks which can worsen diarrhea
- • Monitor for signs of dehydration
🛏️ Comfort Measures
✓ DO:
- • Dress child in light, breathable clothing
- • Use lightweight blanket
- • Keep room comfortably cool
- • Offer tepid (lukewarm) bath if child enjoys it
- • Rest and quiet activities
✗ DON'T:
- • Give cold baths (uncomfortable, can cause shivering)
- • Use rubbing alcohol baths (dangerous)
- • Bundle child in heavy clothing/blankets
- • Force child to eat if not hungry
- • Wake sleeping child to give medication
Febrile Seizures: What Parents Need to Know
Febrile seizures (seizures caused by fever) occur in 2-5% of children between 6 months and 5 years old. While frightening to witness, they're usually harmless.
What They Look Like:
- • Loss of consciousness
- • Jerking movements of arms and legs
- • Eyes rolling back
- • Usually last 1-2 minutes (rarely up to 5 minutes)
- • Child may be sleepy and confused afterward
What to Do:
- 1. Stay calm (seizure won't harm your child)
- 2. Place child on side on soft surface
- 3. Remove nearby objects that could cause injury
- 4. Don't put anything in child's mouth
- 5. Don't restrain child
- 6. Time the seizure
- 7. Call doctor after seizure ends
- 8. Call 911 if seizure lasts more than 5 minutes
Good News:
- • Febrile seizures don't cause brain damage
- • Don't lead to epilepsy in most cases
- • Most children outgrow them by age 5
- • Having one doesn't mean child will have more
Common Fever Myths vs. Facts
MYTH: Fever causes brain damage
FACT: Fever from illness won't cause brain damage, even if it's high. Brain damage from heat occurs only at body temperatures above 107-108°F (42°C), which is extremely rare and usually from external heat sources (like being left in a hot car).
MYTH: All fevers need to be treated with medication
FACT: Fever is helpful—it fights infection. Treat fever only if your child is uncomfortable. A happy, playing child with a fever doesn't necessarily need medication.
MYTH: The height of the fever indicates how sick the child is
FACT: How your child looks and acts is more important than the fever number. A child with 104°F who's playing may be less concerning than a child with 100.5°F who's lethargic.
MYTH: Teething causes high fevers
FACT: Teething may cause slight temperature elevation (under 100.4°F) but doesn't cause high fevers. If your teething baby has a high fever, look for another cause.
MYTH: You should alternate acetaminophen and ibuprofen
FACT: Unless your doctor specifically recommends it, stick with one medication. Alternating increases risk of dosing errors and overdose.
Frequently Asked Questions
Q: Should I wake my child to give fever medication?
No. Sleep is important for healing. If your child is sleeping comfortably, let them sleep. Fever medication is for comfort, not to maintain a "normal" temperature. Wake them only if they seem uncomfortable or distressed while sleeping.
Q: How often should I check my child's temperature?
Check temperature when your child feels warm or seems ill, before giving medication, and to monitor response to treatment. You don't need to check constantly—how your child looks and acts is more important than the exact number.
Q: Can my child go outside with a fever?
Going outside with a fever won't make your child sicker. However, they should rest and avoid strenuous activity. Also consider that fever often indicates a contagious illness, so keep your child home to avoid spreading illness to others.
Q: When can my child return to school after a fever?
Most schools require children to be fever-free for 24 hours without fever-reducing medication before returning. This ensures they're no longer contagious and have recovered sufficiently.
⚠️ Medical Disclaimer
This article provides general information about fever in children and is not intended to replace professional medical advice, diagnosis, or treatment. Always consult with your child's pediatrician if you have concerns about your child's fever, especially for infants under 3 months. Trust your parental instincts—if something doesn't seem right, seek medical attention.