It's the fourth rough night in a row, your baby is gnawing on everything and miserable, and you're stuck on the same question every parent asks: is this teething, or are they actually sick? Take a breath. Most of the time the answer is clear once you know which signs belong to which, and teething gets blamed for a lot it doesn't actually cause.
Here's the short version: teething brings drool, chewing, sore gums, and crankiness around a new tooth. Illness brings a true fever, a runny nose, a cough, diarrhea, vomiting, or a rash. Teething does not cause those. When your baby seems genuinely unwell rather than just cranky, it's worth looking for another cause.
What the science says
Real teething symptoms cluster in the few days around a tooth breaking through the gum. Per the American Academy of Pediatrics and the NHS, the genuine signs of teething are:
- Drooling — sometimes enough to cause a mild drool rash on the chin.
- Chewing and gnawing on fingers, toys, and the crib rail.
- Sore, swollen, tender gums, sometimes with a visible bulge where a tooth is about to surface.
- Irritability and crankiness, especially the day or two before a tooth cuts through.
- A slightly raised temperature — but slightly is the operative word.
Now the part that saves a lot of misplaced worry. Teething does not cause a true fever. It may nudge the temperature up a touch, but anything 100.4°F (38°C) or higher is a real fever from something else — usually a routine virus that happened to show up the same week as a tooth. Teething also does not cause diarrhea, a runny nose, a cough, a rash, or vomiting. Those are signs of illness, not teeth. The research is consistent on this. Our full teething timeline and relief guide walks through what teething does and doesn't do in detail.
A quick side-by-side
When you're squinting at a fussy baby at 2 a.m., this is the split that matters:
Points to teething:
- Drooling and constant chewing on hands and objects
- Red, swollen gums you can feel or see a tooth under
- Crankiness that comes and goes around a tooth, then eases
- No fever, or only a very slight rise; baby is otherwise themselves between fussy spells
Points to illness:
- A true fever of 100.4°F (38°C) or higher
- A runny or stuffy nose, a cough, or congestion
- Diarrhea or vomiting
- A rash anywhere on the body
- A baby who seems genuinely off — listless, won't feed, hard to console even when not actively in pain
Why the overlap, though? Babies who are teething are putting everything in their mouths, which is exactly how they catch the viruses going around. So a tooth and a cold genuinely do arrive together a lot of the time. When both are happening, treat the illness — don't write a fever off as teeth.
What helps either way
A teething baby and a mildly sick baby both want comfort, and a lot of the same gentle measures soothe both:
- For sore gums: a clean finger or damp gauze rubbed firmly on the gum, a chilled (not frozen) teething ring, or a cold washcloth to gnaw.
- For a congested, sick baby: saline drops and gentle suction before feeds and sleep, plus extra fluids.
- For genuine pain or a comfort-affecting fever: the right weight-based dose of acetaminophen, or ibuprofen for babies over 6 months. Dose by weight, not age, and check our infant medication dosing guide — or ask your pediatrician or pharmacist if you're unsure.
What to skip for teething, per the FDA: benzocaine gels, homeopathic teething tablets, and amber teething necklaces. The teething guide covers exactly why.
When to call your pediatrician
Most teething needs patience, not a phone call. But reach out — and treat it as illness, not teeth — if you see, drawn from AAP guidance:
- Any temperature of 100.4°F (38°C) or higher. That's a real fever, not teething. In a baby under 3 months, a rectal temperature of 100.4°F or higher is a medical emergency — call your doctor or go to the ER immediately, even if your baby looks fine. See newborn fever: when to worry.
- A runny nose, cough, congestion, diarrhea, vomiting, or a rash — none of these are teething symptoms.
- Persistent ear-pulling with distress, especially after a cold, which can signal an ear infection rather than teeth.
- A baby who seems genuinely unwell — hard to console, won't feed, unusually sleepy, or just "off."
- Fussiness that's extreme or won't ease with simple comfort measures.
Logging temperatures, symptoms, and rough nights in the TinyWins app keeps the timeline straight, so when you call the nurse line you can say exactly when the fever started and what you've tried.
The bottom line
Teething is drool, chewing, sore gums, and crankiness around a new tooth — and it passes. Illness is a true fever, congestion, a cough, diarrhea, vomiting, or a rash, plus a baby who seems genuinely unwell. Teething does not cause those, and it never causes a true fever. When the two overlap, trust your gut and treat the illness, not the teeth — and remember the one rule that has no exceptions: 100.4°F under 3 months means call now.
This article is educational and not medical advice. Always check with your pediatrician/provider.