Mucocele or Ranula (Bump in Baby's Mouth)
Medically reviewed by Dr. Michael Okonkwo, MD, FAAP · Board-Certified Neonatologist
Content reviewed against published AAP, AAPD, NIH guidelines
Last reviewed:
If your baby has been diagnosed with or you suspect mucocele or ranula (bump in baby's mouth), here is what the evidence says.
The short answer
A mucocele is a painless, fluid-filled bump that develops when a salivary gland duct becomes blocked or damaged, causing saliva to collect under the tissue. It appears as a soft, round, bluish or translucent swelling, most commonly on the lower lip. A ranula is a specific type of mucocele that occurs on the floor of the mouth under the tongue. While they can look alarming, mucoceles are benign and not cancerous. Many small mucoceles resolve on their own, but larger or persistent ones may need to be removed by a pediatric oral surgeon or ENT specialist.
Key takeaways
- A mucocele is a painless, fluid-filled bump that develops when a salivary gland duct becomes blocked or damaged, causing saliva to collect under the tissue. It appears as a soft, round, bluish or translucent swelling, most commonly on the lower lip. A ranula is a specific type of mucocele that occurs on the floor of the mouth under the tongue. While they can look alarming, mucoceles are benign and not cancerous. Many small mucoceles resolve on their own, but larger or persistent ones may need to be removed by a pediatric oral surgeon or ENT specialist.
- Usually normal when: A small, painless, bluish or clear bump on the inner lip that has been present for a short time and your baby is unbothered
- Call your doctor if: A large ranula under the tongue is interfering with feeding, swallowing, or breathing in a young infant
- Varies by age — see the age-by-age breakdown below
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What Parents Should Know
According to AAP, AAPD, NIH guidelines, a mucocele is a painless, fluid-filled bump that develops when a salivary gland duct becomes blocked or damaged, causing saliva to collect under the tissue. It appears as a soft, round, bluish or translucent swelling, most commonly on the lower lip. A ranula is a specific type of mucocele that occurs on the floor of the mouth under the tongue. While they can look alarming, mucoceles are benign and not cancerous. Many small mucoceles resolve on their own, but larger or persistent ones may need to be removed by a pediatric oral surgeon or ENT specialist. At 0-6 months, mucoceles and ranulas in newborns are sometimes present at birth (congenital) and appear as a soft, bluish or translucent swelling on the lip, inside the cheek, or under the tongue. A congenital ranula on the floor of the mouth may occasionally be large enough to interfere with feeding or breathing. Your pediatrician can usually diagnose a mucocele by its characteristic appearance. Most small mucoceles in infants are observed, as they often resolve spontaneously within a few weeks to months. It is generally considered normal when a small, painless, bluish or clear bump on the inner lip that has been present for a short time and your baby is unbothered. However, you should contact your pediatrician promptly if a large ranula under the tongue is interfering with feeding, swallowing, or breathing in a young infant.
Normal vs. Concerning
By Age
What to expect by age
0-6 months
Mucoceles and ranulas in newborns are sometimes present at birth (congenital) and appear as a soft, bluish or translucent swelling on the lip, inside the cheek, or under the tongue. A congenital ranula on the floor of the mouth may occasionally be large enough to interfere with feeding or breathing. Your pediatrician can usually diagnose a mucocele by its characteristic appearance. Most small mucoceles in infants are observed, as they often resolve spontaneously within a few weeks to months.
6-12 months
As your baby begins teething and exploring objects with their mouth, minor trauma to the inner lips and cheeks can damage salivary gland ducts and cause mucoceles. You may notice a smooth, round, dome-shaped bump that is soft to the touch, usually painless, and bluish or clear in color. The bump may fluctuate in size, sometimes appearing larger after meals when saliva production increases. Mucoceles are harmless and your baby should not be in pain.
1-3 years
Toddlers may develop mucoceles from biting their lips or cheeks, or from falls that injure the mouth. If a mucocele keeps coming back after rupturing on its own, your pediatrician may refer you to a pediatric oral surgeon or ENT for definitive treatment. The most common procedure is excision (surgical removal) of the mucocele along with the associated minor salivary gland, which is a brief outpatient procedure. For ranulas under the tongue, marsupialization (creating a drainage opening) may be performed.
3+ years
In older children, mucoceles can recur if the underlying blocked gland is not removed. If your child has a mucocele that repeatedly fills, ruptures, and refills, surgical removal is generally recommended. The procedure is straightforward, performed under local or general anesthesia depending on age and cooperation, and recurrence after complete excision is uncommon. Ranulas that extend below the jaw (plunging ranulas) are rare but may require a more extensive surgical approach.
What to Tell Your Pediatrician
- Describe when you first noticed mucocele or ranula (bump in baby's mouth) and how it has changed over time.
- Note your baby's current age and which age-specific patterns you are seeing.
- Mention if a bump in your baby's mouth has been present for more than 2-3 weeks and is not resolving.
- Mention if the mucocele keeps coming back after rupturing on its own.
- Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
- Bring a list of any questions or observations you want to discuss at the appointment.
What Should You Do?
When to take action
- A small, painless, bluish or clear bump on the inner lip that has been present for a short time and your baby is unbothered
- The bump fluctuates in size but is not growing steadily and does not interfere with feeding
- A mucocele that ruptured on its own and has not recurred
- Your pediatrician has examined the bump and confirmed it is a mucocele
- A bump in your baby's mouth has been present for more than 2-3 weeks and is not resolving
- The mucocele keeps coming back after rupturing on its own
- The bump is growing in size or you are unsure whether it is a mucocele
- A large ranula under the tongue is interfering with feeding, swallowing, or breathing in a young infant
- The area around the bump becomes red, swollen, warm, or painful, suggesting a possible infection rather than a simple mucocele
What You Can Do at Home
- Keep track of when you notice mucocele or ranula (bump in baby's mouth) — noting the time of day, duration, and any triggers can help your pediatrician.
- Remember that a small, painless, bluish or clear bump on the inner lip that has been present for a short time and your baby is unbothered — this is generally within the range of normal.
- At 0-6 months, focus on observation rather than intervention unless your pediatrician advises otherwise.
- Follow any care instructions from your pediatrician. Keep a written log of symptoms to bring to appointments.
- While monitoring at home, seek immediate care if a large ranula under the tongue is interfering with feeding, swallowing, or breathing in a young infant.
Related Conditions
Preventing Early Childhood Cavities (Caries)
Early childhood caries (ECC) is the most common chronic disease in young children, affecting about 23% of US children under age 5. Cavities in baby teeth matter because they can cause pain, infection, and affect the development of permanent teeth. Prevention starts from the first tooth: use a rice-grain-sized smear of fluoride toothpaste, avoid putting baby to bed with a bottle of milk or juice, limit sugary foods and drinks, and schedule the first dental visit by age 1 or within 6 months of the first tooth appearing.
Baby Tooth Turning Gray or Dark
A baby tooth turning gray or dark usually happens after a bump or fall that damages the blood supply inside the tooth. This can happen within days of the injury or weeks later. A darkened tooth does not always mean it is "dead" or infected - many gray teeth remain healthy and eventually fall out normally when the permanent tooth is ready. However, a darkened tooth should be evaluated by a dentist to check for signs of infection.
Related Resources
Frequently asked questions
Is mucocele or ranula (bump in baby's mouth) normal?
When should I call the doctor about mucocele or ranula (bump in baby's mouth)?
When is mucocele or ranula (bump in baby's mouth) normal?
What causes mucocele or ranula (bump in baby's mouth)?
What should I mention to my pediatrician about mucocele or ranula (bump in baby's mouth)?
Is mucocele or ranula (bump in baby's mouth) normal at 0-6 months?
Is mucocele or ranula (bump in baby's mouth) normal at 6-12 months?
Should I go to the ER for mucocele or ranula (bump in baby's mouth)?
Does mucocele or ranula (bump in baby's mouth) go away on its own?
References
Doctor Visit Checklist
Bring this checklist to your next pediatrician visit to discuss Mucocele or Ranula (Bump in Baby's Mouth).
Things to mention
- Describe when you first noticed mucocele or ranula (bump in baby's mouth) and how it has changed over time.
- Note your baby's current age and which age-specific patterns you are seeing.
- Mention if a bump in your baby's mouth has been present for more than 2-3 weeks and is not resolving.
- Mention if the mucocele keeps coming back after rupturing on its own.
- Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
- Bring a list of any questions or observations you want to discuss at the appointment.
Observations to share
- A bump in your baby's mouth has been present for more than 2-3 weeks and is not resolving
- The mucocele keeps coming back after rupturing on its own
- The bump is growing in size or you are unsure whether it is a mucocele
Urgent signs to report immediately
- A large ranula under the tongue is interfering with feeding, swallowing, or breathing in a young infant
- The area around the bump becomes red, swollen, warm, or painful, suggesting a possible infection rather than a simple mucocele
My notes
From ismybabyalright.com — free, evidence-based baby health guides
All content follows our editorial policy and is reviewed against published clinical guidelines.
2,705 evidence-based guides6 authoritative medical sources5 medical advisory board members
Related Resources
Bottom line
Most cases of mucocele or ranula (bump in baby's mouth) are normal. Talk to your pediatrician if a large ranula under the tongue is interfering with feeding, swallowing, or breathing in a young infant.
Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.
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Related Medical Concerns
Preventing Early Childhood Cavities (Caries)
Early childhood caries (ECC) is the most common chronic disease in young children, affecting about 23% of US children under age 5. Cavities in baby teeth matter because they can cause pain, infection, and affect the development of permanent teeth. Prevention starts from the first tooth: use a rice-grain-sized smear of fluoride toothpaste, avoid putting baby to bed with a bottle of milk or juice, limit sugary foods and drinks, and schedule the first dental visit by age 1 or within 6 months of the first tooth appearing.
Baby Tooth Turning Gray or Dark
A baby tooth turning gray or dark usually happens after a bump or fall that damages the blood supply inside the tooth. This can happen within days of the injury or weeks later. A darkened tooth does not always mean it is "dead" or infected - many gray teeth remain healthy and eventually fall out normally when the permanent tooth is ready. However, a darkened tooth should be evaluated by a dentist to check for signs of infection.
My Baby's Head Shape Looks Abnormal
Many babies develop temporary head shape irregularities that are completely normal. A cone-shaped head from vaginal delivery reshapes within days. Mild positional flattening (plagiocephaly) from sleeping on the back is very common and usually improves with repositioning and tummy time. However, head shape changes involving ridges, a persistently bulging fontanelle, or rapid head growth changes should be evaluated to rule out craniosynostosis.
Achondroplasia (Dwarfism) in Babies
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Adenoid Hypertrophy and Breathing
Adenoids are lymphoid tissue located behind the nose that help fight infection in young children. When adenoids become enlarged (adenoid hypertrophy), they can block the nasal airway, causing chronic mouth breathing, snoring, nasal speech, and sleep-disordered breathing. Enlarged adenoids are most common between ages 2-7 and are a leading cause of obstructive sleep apnea in young children. Treatment ranges from watchful waiting and nasal steroids to surgical removal (adenoidectomy) if breathing or sleep is significantly affected.
Adrenoleukodystrophy (ALD) in Babies
X-linked adrenoleukodystrophy (X-ALD) is a genetic disorder affecting about 1 in 17,000 newborns, caused by mutations in the ABCD1 gene on the X chromosome. It primarily affects boys and impairs the breakdown of very long-chain fatty acids (VLCFAs), which accumulate and damage the myelin sheath in the brain and the adrenal glands. The most severe form, cerebral ALD, typically affects boys between ages 4-10 with rapid neurological decline. Newborn screening now enables early detection, and hematopoietic stem cell transplant or gene therapy performed before significant brain involvement can be life-saving.