Teething vs Illness: How to Tell the Difference

6 min read

Quick answer: Teething causes drooling, chewing, swollen tender gums, fussiness, disrupted sleep, slightly red cheeks and at most a slight rise in temperature. It does not cause a temperature of 38°C or higher, diarrhoea, vomiting, body rashes, cold symptoms or refusal to feed; these need a GP or 111. Call 999 or go to A&E for 38°C or higher under 3 months, 39°C or higher at 3 to 6 months, a rash that does not fade, or fever with refusal to feed.

From the Infatot range: the Koda Koala Teething Pair, a teething mitten with a remote-shaped teether in LFGB-grade silicone, named Best Teething Mitten in the Women's Health UK 2025 awards.

What parents need to know

"It must be teething": those four words account for a huge number of delayed medical consultations. Teething is often used as a catch-all explanation for any baby symptom, when in fact the evidence suggests its effects are much more limited than widely believed.

Knowing the difference between what teething actually causes and what it doesn't can help you know when to ride it out, and when to call the GP.

When does teething start?

First teeth typically appear between 4 and 7 months, though it's perfectly normal for first teeth to appear earlier or later. Most children have all 20 primary teeth by age 3. The order is usually: lower front teeth first, then upper front teeth, then working outwards and backwards.

Many babies experience teething with very little fuss at all. Others are clearly uncomfortable. Both are normal.

What teething actually causes

Research and NHS guidance support these as true teething symptoms:

Drooling: Significantly increased saliva production is a hallmark sign of teething.
Chewing and gnawing: Everything goes in the mouth. Counter-pressure on the gums provides some relief.
Swollen, tender gums: You may be able to see or feel the tooth emerging.
Fussiness and irritability: Particularly in the day or two before a tooth breaks through.
Mildly disrupted sleep: Teething discomfort can cause extra night wakings.
Slightly red cheeks: The drool and skin irritation can cause a mild rash around the mouth and chin.
A very slight rise in temperature: Some studies show a very minor temperature elevation (but NOT a high fever).

A baby sitting in a high chair holding a toy

What teething does NOT cause

This is where it's important to be clear:

High fever (38°C or above): Teething does not cause a temperature of 38°C or above. A high fever in a baby is always worth investigating and is not "just teething."
Diarrhoea: While some parents report loose stools during teething, there is no scientific evidence that teething causes diarrhoea. Loose stools alongside other symptoms warrant a GP call.
Vomiting: Not a teething symptom.
Rashes on the body: A rash on the trunk, limbs, or elsewhere is not caused by teething.
Cold symptoms: Sneezing, congestion, and a runny nose are not teething symptoms.
Loss of appetite or refusal to feed: While mild fussiness around feeding can occur, a baby who is refusing feeds should be assessed.

When to get help

Call 999 or go to A&E if your baby:

Is under 3 months old and has a temperature of 38°C or higher, or is 3 to 6 months old and has a temperature of 39°C or higher
Has a very low temperature (less than 36°C), or feels cold to touch or is shivery
Has a stiff neck, or is bothered by light
Has a rash that does not fade when you press a glass against it
Is having a seizure (fit)
Has unusually cold hands and feet, or skin that feels cold or damp (clammy) to touch
Has blue, grey, paler than usual or blotchy skin, lips or tongue (this may be harder to see on brown or black skin)
Is drowsy and hard to wake, is confused, or will not stop crying
Has a weak, high-pitched or continuous cry
Has difficulty breathing (you may notice grunting noises or their tummy sucking in under their ribs), or is breathing very fast
Has not had a pee or a wet nappy in the past 12 hours
Has green or yellow-green vomit, vomits blood, or has vomit that looks like ground coffee
Is not responding like they normally do, or has a high temperature and is not interested in feeding or normal activities

Call NHS 111 or contact your GP urgently if your baby:

Is under 6 months old and you think they have a high temperature
Has a high temperature that has lasted for 5 days or more
Has other signs of illness, such as a rash, as well as a high temperature
Does not want to feed or eat but has no high temperature and is otherwise responding normally
Is not their usual self and you are worried
Shows signs of dehydration, such as nappies that are not very wet, sunken eyes, and no tears when they cry

Get medical advice from your GP or NHS 111 if your baby has a rash anywhere on the body, diarrhoea or vomiting alongside other symptoms, or any other symptom that is worrying you.

Helping with teething discomfort

Cold teething rings: Cooled in the fridge (not the freezer) can help. Avoid teethers that have been recalled. Check the UK Government product safety register.
Gentle gum massage: A clean finger pressed gently on the gum can relieve pressure.
Teething gels: The NHS says there is a lack of evidence that teething gels work, and recommends trying teething rings or sugar-free infant paracetamol or ibuprofen first. If you do use a gel, choose one specially designed for young children (they are only available from pharmacies) and ask a pharmacist for advice.
Paracetamol or ibuprofen: Age-appropriate infant paracetamol (from 2 months) or ibuprofen (from 3 months and 5kg) can be used for teething pain. Always follow dosage instructions and don't use to mask symptoms of illness.
Comfort and cuddling: Sometimes the most effective remedy of all.

A note on amber teething necklaces

Amber teething necklaces have no scientific evidence supporting their effectiveness. More importantly, they present a serious strangulation and choking hazard. The NHS and leading paediatric bodies advise against their use.