Eruption Cyst: A Purple Blue Bump on Your Baby’s Gums

Eruption Cyst: A Purple Blue Bump on Your Baby’s Gums

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Eruption Cyst Baby Molar
©Oral Answers Contributor

Many parents worry when they find that their young child or baby has a bluish purple bump on their gums.  This is a fairly common development and is known as an eruption cyst or eruption hematoma.  For uniformity throughout the article, I will simply refer to them as eruption cysts.

What Are Eruption Cysts?

Eruption Cyst Upper Baby MolarThe easiest way to describe eruption cysts is by talking about how teeth develop.  Your child’s teeth form inside of a protective enclosure in their jaw bone.   When the teeth are done forming, they start to move through the bone, and then through the gums until they make it into the mouth.  An eruption cyst occurs during the tooth’s final entry into the mouth – after it has already made its way through the bone and is just under the surface of the gums.

The protective enclosure which the tooth developed in can leak and allow fluid to accumulate between the tooth and the gums.  If an opposing tooth touches the gums, it may cause fluid and possibly blood to accumulate between the tooth and the gum.  This causes a bruise to form in the gum tissue between the tooth and the outside surface of your child’s gums.  Depending on the amount of blood that accumulates in the eruption cyst, it can be a translucent color, bluish purple, or even dark red and brown.

Although they are unattractive and often cause parents to worry, most eruption cysts are actually painless.

What Causes Eruption Cysts?

Eruption CystThe most widely-accepted theory is that eruption cysts are caused by trauma to the gums a few weeks before a new tooth comes in.  The trauma doesn’t have to be severe — McDonald & Avery’s Pediatric Dentistry states that the trauma occurs as a result of normal chewing.

Another reason eruption cysts occur is due to thickened gum tissues.  This can result from taking certain medications.  Neville’s Oral Pathology textbook hypothesized that one reason eruption cysts occurred in a young child taking cyclosporin was due to “collagen deposition in the gingival connective tissue that resulted in a thicker, less penetrable, pericoronal roof.”  With thicker gums, it may have been more difficult for the tooth to erupt into the mouth, causing an eruption cyst.

Who Can Get Eruption Cysts?

Any child can get an eruption cyst before their tooth erupts into the mouth.  As far as race goes, they are reported to be most common in Caucasian children and they are just as common in boys as in girls.

How Common Are Eruption Cysts?

Nobody knows.  A scholarly article has state, “Prevalence of eruption cyst has not been thoroughly studied.  Extensive review of literature revealed low prevalence of these cysts.”

Many parents may not notice that their child has an eruption cyst or may simply do nothing about it and then note that it goes away.  Due to the fact that many eruption cysts are not documented very well, it’s hard to pinpoint an exact percentage when it comes to how common eruption cysts are.

In an exam of 1,211 children from a Brazilian hospital, it was found that 2 of them had eruption cysts.  That’s only 0.17% that had eruption cysts at the time that they were examined.  However, many more of these children may have had eruption cysts before they were examined.  This would lead me to believe that eruption cysts are much more common than 0.17%.

Where Do Eruption Cysts Occur?

Although it has been debated, most articles (like this one) state that eruption cysts occur most commonly in the upper jaw.  They most commonly occur with the baby incisors, the baby molars, and the permanent first molars.

How Are Eruption Cysts Treated?

Normally eruption cysts don’t need treatment.  The tooth will usually break through the cyst within a few days come into the mouth on its own.  If the eruption cyst persists in the mouth for more than a few weeks, many dentists will make a small incision in the cyst which will allow the tooth to come through.  Depending on the anxiety level of your child, this procedure can usually be done under local anesthesia.

What Else Could It Be?

When we see a swelling over a tooth that is about to erupt, we usually think of eruption cysts.  It is possible that it could be something else though, such as a calcifying odontogenic cystThis case report states, “Other lesions that can cause gingival swellings include peripheral giant cell granuloma, peripheral ossifying fibroma, pyogenic granuloma, and other less common peripheral odontogenic tumors.”

Questions?

Do you have any questions, comments, or concerns about eruption cysts?  Feel free to leave a comment in the comments section below.

I want to especially thank Leigh for sharing the above photo of her 8 month old daughter’s eruption cyst.  If anyone else wants to share their photo, you can email them to OralAnswers at Gmail.com or use this contact form.  Thanks for reading!

Photo Credits All photos provided by Oral Answers Readers

Update 1/7/2012: I just wrote a follow-up post to this one that has two high-quality pictures of eruption cysts above permanent teeth that haven’t yet come in.  Click here to check it out.

16 COMMENTS

  1. Recently I found a cyst that sounds and looks similar to the on listed above. My son is 18 months and should be growing his baby molars (his twin sister’s came in a month ago). Are the molars also found in toddlers or are they only found in babies( under1 year)?

    • Hi Sondra – The baby first molars usually come in while the child is 1 year old, and the baby second molars usually come in while the child is 2 years old. I hope that helps, let me know if you have any other questions. Thanks for your comment!

  2. My LO is 11 months,He got a trauma on his upper jaw with little bleeding.The area is bruised,and it looks exactly as the posted photo in this article.
    His tooth is not erupted yet but it was somehow swelled before the trauma and ready for eruption(i think)

    Do i need to contact a dentist?

  3. My 13 Month old has all 4 baby molars coming in right now. Three of them have broken through, but the last one appears to have this cyst on it. However, it is a “flap” of a blue/gray color with a little blood in it. Is this normal?
    He also on amoxicillin right now as he has an ear infection and cold right now as well- could that be related?
    Thank you.

  4. i’m a dental therapist , i have received a baby of 1 and half mouth bilateral eruption cysts in canines region with a purple color, fluctuate and it is present the time of birth not growing.

  5. Just wondering if its common to have a six year old with 2 of these purple/black spots over his top molar teeth, it has been there for a couple of months now. It does not bother him at all, he has not lost any teeth yet and is almost 7. i know he is different to his sister as at this age she had already lost 4 teeth and grown most of hers. But he has not lost any and seems to be having trouble getting these 2 to come, Is it advisable to give him something to chew on, just like a baby would to break the skin ??? need your advise as he does not like going to the dentist either.

  6. My 14mo has a top right molar coming in and the swelling/color is pretty alarming (to me). He’s had it for 1.5 weeks and although it does not bother him (he’s eating fine and I’ll have him bite down on my finger with it), I wonder when we should give up hoping it’ll resolve on its own. Some websites say a few days and some say a few weeks. The swelling has gone down a bit the past two days (no anti-inflammatory given) and I wonder if that’s a sign the tooth is finally coming through? Thank you Dr Tom!

  7. My 18 month old has a blister type thingy in his mouth where his front tooth should be. when he was a baby he had a purplish dot (very small) on the top of his lower gum. His Dr thought this was from his sucking. Now 18 months later his front teeth have come in except for the one where this blister thing is. I have taken him to a dentist but he does not know what it is.I am afraid this is going to affect his tooth growth, (although his dr says it will not). It is very noticable, and as he gets older it gets bigger. I want to get a second opinion but i dont know where to get it from.

    Very confused

  8. Thank you for the very informative article it has been very useful. My daughter has one of these cysts where her first molar is coming out in the top gums. However I am concerned as the tooth looks like it might be coming out of the side of the top left gums. Is this combination common? Will it self correct or should I have it seen to?

  9. My 4 month old son has one of these according to our dentist. However, it’s been there since birth. Is that normal?

  10. Hi there. My 6 year old son has about 2 teerh that are a little loose in the bottom portion of his mouth, the ones that are loose are his corner teeth the ones he calls vampire teeth. But those 2 are loose, but on the bottom of those teeth he has a small blister that is surrounded by purple. Which looks like to me a bruised blister and it just now start it to bleed. He has it only one tooth and on the other one he doesn’t. Please help because I am worried and so is he. It doesn’t look like to me like when a tooth is ready to come out, yet again I don’t know.

  11. If a child has what looks like an erosion cyst and then it goes away but the tooth never comes through and then a few weeks later has again what looks like an erosion cyst in the same spot and still no tooth coming in is it of concern or should we just wait it out?

  12. Hi! My baby is only 5 1/2 months and he has this on his upper jaw in the same spot. Does this seem a little early? He does not yet have any other teeth. I thought the bottom two teeth came first?

  13. Hi! My baby is 10 months old and he has a purple mass protruding in upper jaw next to his first incisive. I’m thinking its probably an eruption cyst, but I’ve read that it should go away in a matter of day and he has had this for 3-4 weeks. We took him to the dentist and we where told to start brushing his teeth and that eventually the teeth under it will come out… But I’m still worried because there’s no sign of the tooth coming out. What should I do? Thanks!

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