Is My Baby's Fever From Teething? (How to Tell Teething From a Real Infection)
Is My Baby's Fever From Teething? (How to Tell Teething From a Real Infection)
It is 2 a.m., your baby is fussy, the thermometer reads 100.1°F, and you can feel a hard little bump under their gum. You pull up a search bar and type the question every parent eventually types: is teething actually causing this, or is something else going on? Take a deep breath. Teething does affect babies, but the medical evidence on whether it really causes "fevers" is more reassuring — and more specific — than the late-night internet would have you believe. This is a calm guide to telling teething fuss apart from a true infection, based on general American Academy of Pediatrics (AAP) guidance.
This post is general information, not medical advice, and it does not replace your pediatrician. If anything feels wrong, call your nurse line or pediatrician. With that said, here is what the research and the real-world parenting experience tend to agree on.
Can teething really cause a fever?
Teething can cause a small rise in body temperature — usually less than 1°F above your baby's baseline — but it does not cause a true fever of 100.4°F (38°C) or higher. Multiple AAP-cited studies have shown that any temperature above 100.4°F during teething is more likely caused by a separate viral or bacterial illness, not the tooth itself.
In other words, mild warmth on a teething day? Almost certainly the teeth. A clear, sustained fever? Treat it as you would any other fever and look for another cause. That single threshold — 100.4°F — is the dividing line most pediatricians use, and it matches the threshold the AAP uses to define "fever" at any age.
What temperature counts as a "teething fever"?
Most teething babies run between 98.6°F and 100.0°F — slightly warm, but not feverish by medical definition. Anything 100.4°F (38°C) or higher should be treated as a real fever and tracked just like a fever from any other cause, not dismissed as "just the teeth."
Here is a quick reference parents find useful:
| Temperature (rectal or oral) | What it most likely is | What to do |
|---|---|---|
| 98.6–99.4°F | Normal baseline | Comfort measures only |
| 99.5–100.3°F | Mild teething warmth | Comfort measures, keep watching |
| 100.4–102°F | True fever — likely not teething | Track the fever; look for other symptoms |
| 102°F or higher | Significant fever — definitely not teething | Call the pediatrician for guidance |
| Any fever in baby under 3 months | Medical emergency regardless of cause | Call pediatrician or go to ER immediately |
For babies under 3 months, any rectal temperature of 100.4°F or higher needs immediate medical evaluation — no home guidance, no waiting it out, no blaming the teeth. That rule does not change just because there is a tooth coming in.
How do I tell teething from a real infection?
The clearest tell is the symptom pattern. Teething shows up in the mouth and mood — drool, gum-chewing, mild fussiness, slightly poor sleep. Infections show up in the whole body — sustained fever above 100.4°F, runny nose, cough, ear-pulling, rash, vomiting, diarrhea, or unusual sleepiness. If the symptoms are below the chin, suspect infection.
Here is a side-by-side most pediatricians would recognize:
| Symptom | Likely teething | Likely something else |
|---|---|---|
| Extra drool | Yes | Possible, but usually with other symptoms |
| Chewing on hands or toys | Yes | No |
| Red, swollen gums | Yes | No |
| Mild fussiness, especially evening | Yes | Possible |
| Temperature under 100.4°F | Yes | Possible |
| Sustained fever 100.4°F or higher | No | Yes |
| Runny nose with colored mucus | No | Yes (cold, sinus) |
| Cough or wheezing | No | Yes (cold, RSV, flu) |
| Pulling at one ear | No | Yes (ear infection) |
| Diarrhea or vomiting | No | Yes (stomach bug) |
| Rash anywhere | No | Yes (viral rash, hand-foot-mouth) |
| Lethargy / very hard to wake | No | Yes — call pediatrician now |
If you can check off two or more boxes in the right column, do not let "she's teething" be the only story. Both can be true at the same time — your baby can be teething and fighting a virus.
How long does a teething fever last?
The mild warmth that comes with teething typically lasts one to three days around the day a tooth breaks through the gum, and resolves on its own. If a temperature stays elevated for more than three days, or climbs above 100.4°F at any point, it is almost certainly not the teeth — it is time to track it as an illness and call the pediatrician if it persists.
Teething is also not a constant background condition. Babies cut their first teeth around 6 months and continue through about 30 months, but the active discomfort tends to come in short waves — a fussy day or two, then back to normal. A baby who has been "teething" for a solid week with a fever is usually a baby who has caught something on top of teething.
Why does my teething baby seem so miserable?
The discomfort of teething is real even when the fever is not. Pressure from a tooth pushing through gum tissue, plus the extra saliva that triggers a rash on the chin and chest, is genuinely uncomfortable — your baby is not exaggerating. Studies estimate that 70–80% of babies show at least mild teething symptoms, even though only a small fraction run any measurable temperature change.
What you may see during an active teething phase:
- Increased drooling, sometimes soaking through bibs
- A faint pink rash on the chin, neck, or chest from constant saliva
- Chewing or biting on fingers, toys, or even your shoulder
- Waking more often at night, especially in the early evening
- Slightly reduced appetite, especially for warm or acidic foods
- Pulling at the ears or cheeks (sometimes confused with ear infection — see next section)
What you should not see, and what should make you stop blaming the teeth: high fever, refusing all liquids, listlessness, breathing difficulty, a stiff neck, or a rash that looks like little purple dots. Those are not teething — those are reasons to call your pediatrician or 911 right away.
Which illnesses look like teething but are not?
Several common baby illnesses peak in the same 6–24 month window as teething and share overlapping symptoms — which is why "it's just the teeth" is one of the most over-used phrases in baby forums. Ear infections, viral colds, roseola, and hand-foot-mouth disease all overlap with teething age and can produce fussiness, drool, and reduced appetite.
Three to watch for:
- Ear infection. Babies pull at one ear (not both), the fever climbs above 101°F, sleep gets dramatically worse lying down, and there may be a runny nose preceding it. Often follows a cold.
- Roseola. Three to five days of high fever (often 102–104°F), then the fever breaks and a rosy rash appears on the chest and back. The fever is the giveaway — teeth would never cause that.
- Hand-foot-mouth disease. Mouth sores, drooling, and reduced eating can look like teething until small red spots appear on the hands, feet, or buttocks. Hand-foot-mouth is contagious and worth flagging with daycare.
When in doubt, the rule the AAP repeats is the cleanest one: treat a fever of 100.4°F or higher as a fever, regardless of whether teeth are coming in. That single rule prevents most missed infections.
What can I do to comfort a teething baby with a low fever?
For the mild warmth and gum discomfort of teething, comfort measures work better than medicine. Chilled (not frozen) teething rings, a clean cold washcloth to chew on, gentle gum massage with a clean finger, and extra cuddle time are the AAP's first-line suggestions. Most babies settle within 20–30 minutes of consistent comfort.
A few details that matter:
- Cold, not frozen. Frozen teethers can bruise gums or hurt new teeth coming through. Refrigerate, do not freeze.
- Skip the amber necklaces and topical numbing gels. The AAP and FDA both warn against benzocaine gels for babies under 2 due to a rare but serious blood-oxygen risk, and amber necklaces pose a strangulation hazard with no proven benefit.
- Acetaminophen or ibuprofen are sometimes appropriate — but only at weight-based pediatric doses, only for babies old enough for the medicine, and only with your pediatrician's general guidance. Do not eyeball it. The Tempy app's medication tracker uses your baby's weight to calculate the right amount and remembers the last-given time so you do not double-dose at 3 a.m. — but it is a tool to support, not replace, your pediatrician's instructions.
- Skin care. Pat (do not wipe hard) drool away and apply a thin layer of plain petroleum-jelly-style barrier balm to prevent the drool rash from getting raw.
When should I call the pediatrician about a teething fever?
Call the pediatrician if any of these are true: a baby under 3 months old has any rectal temperature of 100.4°F or higher, a baby 3–6 months old has a fever of 101°F or higher, an older baby has a fever above 100.4°F that lasts more than 24 hours, or your baby shows any red-flag symptom (stiff neck, breathing trouble, rash, lethargy, refusing fluids, or seizure). Trust your gut — pediatricians prefer a false alarm to a missed infection.
A short "call now" list to keep on the fridge:
- Any fever in a baby under 3 months → call pediatrician or go to ER immediately
- Fever above 102°F at any age → call the pediatrician
- Fever lasting more than 3 days → call the pediatrician
- Refusing all fluids, no wet diaper for 6+ hours → call the pediatrician
- Trouble breathing, persistent vomiting, stiff neck, purple/dot-like rash, or febrile seizure → call 911
You are not over-reacting by calling. Pediatric nurse lines exist for exactly this reason, and they would rather hear from you at midnight than have you wait until morning.
Try Tempy
Tempy is a free fever care manager for parents — log temperatures, get safe-window reminders for medicine, share readings with a co-parent, and see when the pattern looks "call the doctor" versus "ride this out." It is designed to support — not replace — your pediatrician.
Frequently Asked Questions
Can teething cause a true fever in my baby?
Teething can cause a slight rise in body temperature, usually less than 1°F above your baby's baseline, but it does not cause a true fever of 100.4°F (38°C) or higher. Any temperature above 100.4°F during teething is more likely due to a viral or bacterial infection.
How can I tell if my baby's fever is from teething or an infection?
Teething symptoms are mostly localized to the mouth and mood, such as drooling, gum-chewing, and mild fussiness with temperatures below 100.4°F. A true infection usually involves sustained fever above 100.4°F and additional symptoms like runny nose, cough, rash, vomiting, or unusual sleepiness.
What temperature range is considered a 'teething fever'?
Temperatures between 99.5°F and 100.3°F may be mild warmth related to teething and can be managed with comfort measures. Temperatures of 100.4°F or higher should be treated as a real fever and monitored closely for other symptoms.
How long does a teething-related temperature last?
Mild warmth associated with teething typically lasts one to three days around the time a tooth breaks through the gum and resolves on its own. If a fever lasts more than three days or rises above 100.4°F, it is likely caused by an illness and requires medical attention.
When should I call the pediatrician about my baby's fever during teething?
Call the pediatrician immediately if your baby under 3 months has a fever of 100.4°F or higher, or if any baby has a fever above 102°F, a fever lasting more than three days, refuses fluids, shows breathing difficulties, rash, lethargy, or seizures. Trust your instincts and seek medical advice if concerned.
Continue reading
How Do I Bring Down My Child's Fever Without Medicine? (8 Pediatrician-Backed Comfort Measures)
A pediatrician-grounded guide to lowering your child's fever naturally — what comfort measures actually work, what to avoid, and when home care is enough versus when to call the doctor.
Can I Alternate Tylenol and Motrin for My Child? (A Safe-Schedule Guide for Parents)
A pediatrician-grounded parent guide to alternating Tylenol and Motrin for a child fever — safe intervals, when alternating helps, when to stop, and how to track every dose without losing your mind.
When Should I Take My Child to the ER for a Fever? (A Red-Flag Guide by Age)
When a child's fever needs the emergency room: red-flag symptoms by age, temperature thresholds that mean call 911, and how to decide between the ER, urgent care, and your pediatrician.