Eruption Cyst

Overview

An eruption cyst is a small, soft, fluid-filled swelling that can appear in the gums over a tooth that is about to come through. It is sometimes called an eruption hematoma (a collection of blood-tinged fluid) when it looks bluish or purple. The swelling is a harmless sac of fluid that sits on top of the erupting tooth, and it usually goes away on its own once the tooth breaks through the gum.

Yes. Eruption cysts are one of the more common gum findings in young children. They are seen often in paediatric dental practice and are usually noticed by a parent or a dentist.

They mostly affect infants and children, typically between about 6 months and 12 years, because this is when baby teeth and the first permanent teeth are coming through. They can occasionally happen with a late-erupting tooth in a teenager or adult, especially a wisdom tooth.

Symptoms

Common symptoms

• A small, round, soft swelling on the gum over a tooth that is coming through
• The swelling may look clear, bluish, purple, or red-tinged
• It is usually painless, or only mildly tender when touched
• The swelling may change size, sometimes getting bigger before the tooth breaks through
• The tooth underneath may feel loose or look like it is pushing up

Symptoms in children

• A visible bubble or lump on the gum, often noticed while brushing or during a routine look in the mouth
• Mild discomfort or dribbling in babies who are teething
• Sometimes a baby may chew or press on the area
• Most children are not bothered by it at all and eat and sleep normally

Symptoms in older adults

• Uncommon in adults, but can occur over a wisdom tooth or a tooth that is slow to come through
• May be noticed as a soft swelling at the back of the gum
• Any new gum swelling in an adult should be checked by a dentist to rule out other causes

Causes

Main causes

• Fluid builds up between the erupting tooth and the thin layer of tissue covering it, forming a small sac
• The sac can fill with clear fluid or with a little blood, which gives it a bluish or purple look
• It happens as part of normal tooth eruption, not because of poor hygiene or anything the child did

Risk factors

• Being at the age when teeth are coming through, especially between 6 months and 12 years
• A tooth that is slow or difficult to erupt
• A history of trauma or inflammation near the gum in some cases
• Wisdom teeth or other late-erupting teeth in older children and adults

When to see a doctor

See a doctor urgently if:

• The swelling is very painful, hot to touch, or leaking pus
• Your child has a fever or seems generally unwell
• The swelling is large and getting bigger quickly, or makes it hard to eat, drink, or swallow
• There is bleeding that will not stop

Book a routine appointment if:

• A gum swelling over an erupting tooth that has not gone away after a few weeks
• The area looks bluish or purple and you are unsure what it is
• Your child is in discomfort or is not eating well
• Any new gum lump in an adult

Diagnosis

A dentist or doctor can usually tell what it is just by looking in the mouth and asking a few questions about when the swelling appeared and whether it is painful. Because the appearance is quite typical, tests are often not needed.

Tests that may be done

• A careful look inside the mouth, sometimes with a small mirror
• A dental X-ray may be taken if the dentist wants to check the position of the tooth underneath or rule out other causes
• In rare cases, if the swelling does not settle, a small sample of the fluid may be checked, or the tissue removed and examined in a laboratory

What to expect at your appointment

The appointment is usually quick and gentle. Your dentist or doctor will explain what they see, whether anything needs to be done, and what changes would mean you should come back. Most families leave with simple reassurance and advice on keeping the mouth clean.

Treatment

In most cases no treatment is needed. The cyst usually opens or shrinks by itself as the tooth breaks through the gum. The main focus is keeping the mouth clean, watching for changes, and making sure your child is comfortable.

Self-care at home

• Keep brushing gently with a soft toothbrush; do not scrub or burst the swelling
• Encourage your child not to poke, bite, or pick at the lump
• Offer soft foods and cool drinks if the area feels tender
• Rinse the mouth gently with plain water after meals if your child is old enough to spit
• Note any changes in size, colour, or pain, and mention them at the next dental visit

Medical treatments

If the swelling is large, painful, or infected, a dentist may open it to let the fluid out, or remove the small piece of tissue covering the tooth so the tooth can come through. This is a minor procedure done with local numbing (medicine that makes the area numb). Sometimes antibiotics are prescribed by a clinician if there are signs of infection; this is a decision for your dentist or doctor, and you should not use leftover or borrowed medicines. Pain relief should be discussed with a pharmacist or clinician, who will advise what is suitable for your child's age.

When is surgery considered?

A small procedure may be suggested if the cyst is very large, keeps coming back, is painful, or shows signs of infection. It is usually quick, done in the dental chair, and recovery is normally straightforward. Your dentist will explain the options and answer any questions before going ahead.

Living with this condition

Most children carry on with normal eating, drinking, and play. Keep up usual tooth brushing and check the area now and then so you can tell your dentist about any changes. It can help to write down when you first noticed the swelling and whether it is changing.

Lifestyle tips

• Keep regular dental check-ups so the area can be watched as the tooth comes through
• Help young children brush twice a day with a fluoride toothpaste suitable for their age
• Avoid sugary snacks and drinks between meals as part of general mouth care
• Tell your dentist if your child has habits like tooth grinding or thumb sucking that might affect the gums

Diet and exercise

No special diet or exercise changes are needed. If the area is tender, soft foods and cool drinks can feel soothing. There is no reason to stop normal play or sport.

Mental health and emotional wellbeing

A lump in a child's mouth can be worrying for parents, especially if it looks blue or purple. It can help to remember that eruption cysts are common and usually harmless. If you feel anxious, ask your dentist to explain what they see and what to watch for. For children, a calm, simple explanation is usually enough. If worry is affecting your sleep or mood, speak to your doctor or a mental health professional; crisis support is available through your local health service or emergency number if you feel unsafe.

Prevention

Eruption cysts cannot really be prevented because they happen as part of normal tooth eruption. Good oral hygiene, regular dental check-ups, and prompt attention to any gum injury help keep the mouth healthy and make sure any changes are checked early.

Screening programmes

There is no specific screening programme for eruption cysts. Routine dental check-ups, and looking in your child's mouth now and then, are the best way to notice anything new.

Complications

If left untreated

• In most cases nothing happens and the cyst goes away on its own
• Occasionally the swelling can become infected, causing pain, pus, fever, or a generally unwell feeling
• Rarely, a large cyst may delay the tooth coming through or cause the tooth to come through in an unusual position
• Very rarely, a lump that does not settle may need to be examined more closely to rule out other causes

Long-term outlook

The outlook is very good. Most eruption cysts settle without treatment once the tooth erupts, and children usually have no lasting problems. If a small procedure is needed, it is generally quick and well tolerated. Keep up regular dental visits and speak to your dentist if anything changes.

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