Eruption Cysts

Have you noticed a small bump on your child’s gums and are wondering what it might be? It could be an eruption cyst — a common part of growing up that many parents haven’t heard of until it appears. In this guide, Dr Ellie, our Brisbane Paediatric Dentist, breaks it down simply so you’ll know what to expect and when to take action.

What Are Eruption Cysts?

Sometimes, when a child’s tooth is about to come through the gums, a soft, bubble-like swelling can appear on the gum. This is called an eruption cyst. It’s usually harmless and is most often seen right before a baby or adult tooth breaks through. This bubble forms when fluid collects in the tissue around the developing tooth. In some cases, it may look dark or bluish — this is known as an eruption hematoma, which happens when a little bleeding occurs inside the cyst, often due to minor bumps or pressure from chewing.

Most of the time, these cysts disappear on their own once the tooth erupts through the gum.

How Do Eruption Cysts Happen?

An eruption cyst forms when the soft tissue around a tooth, called the dental follicle, fills with fluid just before the tooth comes through the gum. This happens as the tooth moves up toward the surface, creating a space that can sometimes expand and become visible as a swelling. We still don’t fully understand why this happens in some children and not others, but the swelling may be influenced by how the tissue and fluid respond to the erupting tooth. If there’s bleeding into the fluid, possibly caused by chewing or slight trauma, it leads to what we call an eruption hematoma.

Technically, eruption cysts are similar to a type of cyst known as a dentigerous cyst — but with one key difference: dentigerous cysts form around unerupted teeth still inside the bone, while eruption cysts happen in the soft gum tissue once the tooth has already broken through the bone.

Eruption Cysts: Etiology and Prevalence

Commonality and Nature

Eruption cysts are benign, developmental cysts that typically accompany the eruption of primary or permanent teeth. They are generally considered a normal variation of tooth eruption and are not pathological unless they become infected. ​

Location and Affected Teeth

These cysts are more frequently observed in the maxilla (upper jaw). Eruption hematomas, a variant containing blood, are often seen in the region of the primary second molar or the first permanent molar. ​

Occurrence in Newborns and Children

In newborns, eruption cysts can occur due to the presence of natal or neonatal teeth, although this is relatively rare. Older children with both deciduous (baby) and permanent teeth can also develop eruption cysts during the normal process of tooth eruption.

Treatment of Eruption Cysts

In most cases, eruption cysts are harmless and resolve on their own as the tooth erupts. Typically, the tooth breaks through the gum tissue within a few days or weeks, and any associated swelling or discolouration subsides naturally.​

However, intervention may be necessary if the cyst:​

• Causes discomfort due to biting trauma from opposing teeth​
• Becomes infected​
• Persists without signs of resolution​

Treatment options include:

• Surgical exposure: Making a small incision in the cyst under local anesthesia to facilitate tooth eruption. This is a straightforward procedure that provides immediate relief.​
• Marsupialisation: In rare cases where the cyst recurs or is particularly large, creating an opening in the cyst and suturing its edges to the surrounding gum tissue can help the tooth erupt and allow the cyst to shrink.​
• Antibiotic therapy: If the cyst becomes infected and the child shows systemic symptoms, such as fever or malaise, antibiotics may be prescribed.​

Special considerations:

• In newborns, simple eruption cysts typically do not require local anesthesia for treatment.​
• During any intervention, it’s crucial to protect the airway, especially in very young children.​

Overall, most eruption cysts do not require treatment and resolve without complications. Regular dental check-ups with your Brisbane Dentist can help monitor the situation and ensure proper oral health.

What Parents Should Know About Eruption Cysts

Reassurance

Eruption cysts are common and usually nothing to worry about. They happen when a tooth is about to come in and are not dangerous. These cysts are not cancer or a serious disease. If they show up on both sides of a newborn’s mouth and look the same, they are almost always harmless.

Appearance

You may see a soft, bluish bubble on your child’s gums where a tooth is coming in. If there’s a little bleeding inside, it can look darker—blue to blue-black. This is called an eruption hematoma.

Spontaneous Resolution

Most of the time, you don’t need to do anything. The swelling usually goes away on its own once the tooth comes through the gums.

When to Seek Dental Advice

It’s a good idea to check in with a dentist if:

• Your child feels pain or discomfort when biting on the area.
• The area looks more swollen, red, or painful — these could be signs of infection.
• The tooth hasn’t come in after a while, even though the cyst has been there for some time.
• You’re unsure if it’s really an eruption cyst — some other conditions can look similar.

Differential Diagnosis

In rare cases, other conditions (like blood vessel growths or certain tumours) can look like eruption cysts, especially in newborns. A dentist can usually tell the difference with a simple exam. For example, pressing gently on the area may help see if it changes colour, which can suggest it’s a blood vessel issue instead.

Complications

Problems from eruption cysts are rare. The main concerns are:

• Infection
• Mistaking it for another type of lesion — this is important because cutting into a blood vessel lesion by mistake could cause heavy bleeding.

Treatment Is Usually Minimal

In most cases, no treatment is needed beyond keeping an eye on it. If your child has discomfort or the area gets infected, the dentist may:

• Make a small cut to help the tooth come out.
• In rare cases, suggest a small procedure (like marsupialization) if the cyst keeps coming back.
• Give antibiotics if there are signs of infection.

Frequently Asked Questions

What is an eruption cyst?

An eruption cyst is a soft, fluid-filled bump that appears on a child’s gums just before a new tooth comes in. It usually forms when fluid builds up in the gum tissue right above the tooth that’s about to erupt. Sometimes, if there’s a little bleeding inside, the bump may look bluish or dark — this is called an eruption hematoma. These cysts are common, not harmful, and typically go away on their own once the tooth breaks through the gums.

How can I tell if my child has an eruption cyst?

You may notice a smooth, round, or slightly raised swelling on your child’s gums, usually where a tooth is getting ready to come in. The bump may look clear, bluish, or even dark purple, especially if there’s bleeding under the surface. It doesn’t usually cause pain, but if your child bites on it or it becomes irritated, it might become sore.

What causes eruption cysts in children?

Eruption cysts happen when fluid collects in the soft tissue over a tooth that’s getting ready to come in. This fluid comes from the normal tissue that surrounds the developing tooth, called the dental follicle. As the tooth pushes toward the surface, the pressure can cause the tissue to stretch and trap fluid, forming a bubble-like cyst. In some cases, a little bleeding from chewing or bumps to the area can mix with the fluid, creating a darker cyst called an eruption hematoma.

Are eruption cysts painful for my child?

Most eruption cysts are not painful and go unnoticed by children. However, if the cyst is bumped or bitten, or if it becomes swollen, it might feel a bit sore or tender.

How long does an eruption cyst typically last?

An eruption cyst usually lasts for a few days to a few weeks, depending on how quickly the tooth breaks through the gum. Once the tooth erupts, the cyst generally disappears on its own without treatment. If the swelling doesn’t reduce or the tooth doesn’t come through after a few weeks, it’s best to check in with a dentist.

Can eruption cysts become infected?

Yes, although it’s uncommon, eruption cysts can become infected, especially if they’re irritated by chewing or if bacteria enter the area. Signs of infection may include increased redness, swelling, tenderness, pus, or your child feeling generally unwell or developing a fever. If any of these signs appear, prompt dental review is important to manage the infection safely.

Should I take my child to the dentist if I notice an eruption cyst?

In most cases, an eruption cyst is harmless and doesn’t need dental treatment. However, it’s a good idea to have your child checked by a dentist, especially if the cyst is large, painful, hasn’t gone away after a few weeks, or if you’re unsure whether it’s a cyst or something else. Dentists can easily confirm the diagnosis and make sure there are no complications. A quick check-up can offer reassurance and help avoid unnecessary concerns.

Is it safe to let an eruption cyst burst on its own?

Yes, it’s generally safe if an eruption cyst bursts naturally as the tooth erupts. The fluid inside is typically harmless and should drain on its own without causing problems. However, if the area looks red or swollen, or your child seems uncomfortable afterwards, it’s best to see a dentist to rule out any infection.

Can eruption cysts occur in both baby and permanent teeth?

Yes, eruption cysts can form over both baby (deciduous) and permanent teeth. They’re most commonly seen in young children when baby molars or front teeth are coming through, but they can also appear during the mixed dentition stage when permanent teeth are erupting. The cyst forms when fluid builds up in the soft gum tissue over a tooth that’s about to emerge. It’s a normal part of development for some children and usually not a cause for concern.

Is there a way to prevent eruption cysts?

Unfortunately, there’s no proven way to prevent eruption cysts, as they’re part of the natural tooth eruption process for some children. Regular dental visits can help detect and manage them early if they do occur.

When should I be concerned about an eruption cyst?

While most eruption cysts are harmless and go away on their own, there are some signs that mean it’s worth seeing a dentist. If the swelling becomes painful, red, or appears to be infected (for example, if there’s pus or your child has a fever), it should be checked. You should also seek advice if the cyst doesn’t go away after a few weeks or if you’re unsure whether it’s actually an eruption cyst. Early dental assessment can help rule out other conditions and make sure your child’s teeth are developing normally.

Can eruption cysts cause delays in tooth eruption?

Eruption cysts don’t usually stop a tooth from coming through, but in some cases, they may slow down the process slightly. This is more likely if the cyst is large or if there’s swelling that puts extra pressure on the gums. If the tooth hasn’t erupted after a reasonable amount of time, it’s a good idea to get a dental check-up.

Are eruption cysts a sign of poor oral hygiene?

No, eruption cysts are not caused by poor brushing or hygiene habits. They occur as a natural part of the tooth eruption process and are influenced by the way the gum tissue and tooth interact, not by plaque or food. Keeping up good oral hygiene is still important for overall dental health, but eruption cysts can happen even in very well-cared-for mouths.

Tailored Dental Care for Children with Additional Needs

Teething changes, like eruption cysts, can sometimes feel more challenging for children who struggle with new sensations or changes in routine. If your child has special needs, we can adapt the visit to suit their comfort—keeping things calm, explaining each step, and moving at a pace that feels right for them. You can read more about how our kids dentist for special needs in Brisbane supports children with additional needs, learn about dental care for special needs children in Brisbane, or visit Dr Ellie Nadian – Brisbane special needs dentist for more details.

Helping Your Child Smile Through Every Stage of Tooth Development

Eruption cysts can be a normal part of growing up, but it’s always reassuring to have a trusted dental team by your side. If you’ve noticed a bump on your child’s gums or have any concerns about how their teeth are coming in, we’re here to help with gentle care and expert advice.

We also offer Sleep Dentistry in Brisbane using general anaesthesia and laughing gas for children who feel nervous or overwhelmed during treatment.

We’ve partnered with Humm and Supercare to give you more breathing room when it comes to managing dental costs. Call us today on (07) 3343 4880.