Why Do My Child's Gums Look Swollen Around a New Tooth?

Mild, localized gum swelling around a newly erupting tooth is usually normal and lasts a few days to two weeks as the tooth pushes through the tissue. Pus, facial swelling, fever, or swelling that lingers beyond two weeks may signal infection or pericoronitis and should be evaluated by your dentist promptly.

We get this question a lot. A parent notices a puffy red bump where a new tooth is poking through, and the worry starts. Most of the time, it's the body doing exactly what it should. Sometimes it isn't. The trick is knowing how to tell the difference.

At La Mirada One Dental, we see this almost daily, especially with families coming in from La Mirada USD elementary schools when the 6-year molars start arriving. Here's what we tell parents.

Is it normal for gums to swell when a new tooth comes in?

Yes. When a tooth pushes up through the gum, the tissue stretches, breaks, and inflames as part of the process. That inflammation is exactly what swelling is. It's expected.

According to the American Academy of Pediatric Dentistry (AAPD), primary teeth typically begin erupting around 6 months of age, and most children have all 20 baby teeth by age 3. Then comes round two. The American Dental Association notes that permanent first molars typically come in around age 6, and second molars around age 12. That means most kids go through eruption swelling twice in their lives. Sometimes more.

A mom from the Hillsborough neighborhood brought her 6-year-old in last spring after noticing a red, puffy spot way in the back of her son's mouth. He'd just started first grade at La Mirada USD and was complaining his "back gum hurt." It was a 6-year molar coming through. Completely normal. We showed her what to watch for and sent them home with simple care instructions.

What does a normal eruption swelling look like?

Normal eruption swelling has a few telltale signs:

• It's localized to one spot, right over the tooth that's coming in

• The area is pink to slightly red, maybe a little shiny

• It lasts a few days to about two weeks

• Your child may drool more, chew on everything, or get fussy

• No fever, no pus, no facial swelling

If you gently press the area, your child might pull away because it's tender. That's fine. Tender is normal. Severe pain is not.

What is an eruption cyst and should I worry?

This one scares parents the most. An eruption cyst looks like a bluish, purplish, or dark red bubble of fluid sitting right on top of an incoming tooth. It can look alarming. It usually isn't.

The AAPD describes eruption cysts as benign, self-limiting lesions that almost always resolve on their own when the tooth breaks through the surface. Surgery is rarely needed. We just keep an eye on it at routine visits.

If you see a small blood blister appearance over an incoming tooth and your child is otherwise comfortable, that's most likely what it is. Don't poke it. Don't pop it. Let the tooth do its work.

When swollen gums signal something more serious

This is where parents need to pay attention. Some swelling is not eruption. It's infection. Call us if you see:

• Pus coming from the area, or a foul taste in the mouth

• Facial swelling, especially around the cheek or jaw

• Fever above 101°F combined with gum swelling

• Swelling that lasts longer than two weeks

• A small flap of gum over a partially erupted molar that keeps getting puffy and sore

That last one has a name: pericoronitis. The Journal of Oral and Maxillofacial Surgery describes it as inflammation of the soft tissue around a partially erupted tooth, and it's most common around erupting molars. Food and bacteria get trapped under the gum flap. The area swells. The cycle repeats. We see this often in kids around 6 and 12, right when their molars are halfway in.

Important note for babies: the American Academy of Pediatrics is clear that teething does not cause high fever. A fever above 100.4°F in an infant warrants evaluation by their pediatrician. Don't blame a real fever on teething.

How to soothe an erupting tooth at home

For babies and toddlers:

• A cold (not frozen) teething ring

• A clean finger to gently rub the gum

• Extra patience. Eruption is uncomfortable.

For older kids:

• Soft, cool foods like yogurt, applesauce, or smoothies

• Gentle brushing around the area with a soft toothbrush

• Age-appropriate acetaminophen or ibuprofen, dosed per your pediatrician's guidance

• Warm salt water rinses for kids old enough to spit

One important warning. The FDA has cautioned against using over-the-counter benzocaine products for teething in children under 2 years old because of a rare but serious risk of methemoglobinemia. Skip the numbing gel. There are safer ways.

When to call La Mirada One Dental

Trust your instincts. If something looks off, call. We'd rather see your child for a quick look than have you worry for days.

Call us at (562) 777-1234 if:

• Swelling has lasted more than two weeks

• You see pus, persistent bleeding, or smell something foul

• Your child refuses to eat or drink

• There's any facial swelling or fever

We offer same-day appointments for urgent concerns, and our Saturday hours work well for parents commuting in from Cerritos, Norwalk, and Whittier who can't take time off during the week. Our office on Imperial Highway, near the Walmart Neighborhood Market, is easy to reach from the I-5 and Beach Boulevard.

Eruption is uncomfortable, not dangerous. Infection is the opposite. Knowing which one you're looking at is half the battle.

Frequently Asked Questions

How long does gum swelling from a new tooth last?

Most eruption-related swelling resolves within a few days to two weeks. Once the tooth breaks through the gum surface, the inflammation usually settles quickly. If swelling persists beyond two weeks, or worsens instead of improving, we recommend an evaluation to rule out infection or trapped debris under a gum flap.

Can I pop an eruption cyst on my child's gum?

No. Please don't. Eruption cysts are sterile, fluid-filled sacs that protect the incoming tooth, and they almost always resolve on their own when the tooth erupts. Trying to drain or pop one at home can introduce bacteria and cause a real infection. If the cyst looks unusually large or doesn't resolve, we can evaluate it.

Is it safe to use teething gels on babies?

The FDA specifically warns against over-the-counter benzocaine teething products in children under 2 years old due to the risk of methemoglobinemia, a serious blood condition. Safer options include a chilled (not frozen) teething ring, gentle gum massage with a clean finger, and acetaminophen if your pediatrician approves it.

Why are my older child's gums swollen around their back molars?

This is often pericoronitis, where a gum flap over a partially erupted 6-year or 12-year molar traps food and bacteria. It's very common in elementary and middle school kids. Warm salt water rinses help, but if swelling recurs or comes with pain, we should take a look and clean under the flap.

What's the difference between teething pain and a gum infection?

Teething pain is localized, mild to moderate, and improves day by day as the tooth emerges. Infection involves pus, foul taste or odor, facial swelling, fever above 101°F, or pain that gets worse instead of better. When in doubt, call us. A two-minute look is easier than days of guessing.

We're here when you need us

Whether it's your toddler's first tooth or your fifth-grader's incoming molar, we treat every parent concern as a real one. No judgment, no rushing. Dr. Park and our team at La Mirada One Dental are happy to take a look, even if everything turns out to be normal. That peace of mind is worth the visit.

Call (562) 777-1234 or book online to schedule a visit. We're at 14930 E Imperial Hwy, Suite D, La Mirada, CA 90638.