Mucous cysts are small, fluid-filled sacs that tend to develop in the mouth or on the fingers and toes.

This article looks at the different types of mucous cyst, their causes, and how they can be treated.

There are two main types of mucous cysts that this article looks at:

Oral mucous cysts

Oral mucous cysts develop in the mouth. They appear near salivary gland openings, often on the lips or the floor of the mouth.

A cyst on the floor of the mouth is known as a ranula. A cyst on the gums is called an epulis. They can also develop around a piercing.

Oral mucous cysts are more common in people who are under 30 years of age.

Digital mucous cysts

Mucous cysts can also develop in other areas of the body besides the mouth.

Digital cysts appear as firm sacs near the joints of the fingers or toes. This type of cyst forms as an extension of the joint. It is also possible for them to develop away from the joint, such as near the base of a fingernail or toenail.

Digital mucous cysts are more common in older adults, typically in people who are more than 70 years of age.

Oral mucous cysts are often the result of injury or damage to the lips or inner mouth. Common causes of this include:

  • lip biting
  • sucking the inner cheek
  • lip sucking
  • piercings
  • abnormal teeth growth

Oral mucous cysts that develop on the floor of the mouth are thought to be caused by a blocked salivary gland beneath the tongue.

It is unclear exactly what causes a digital mucous cyst to occur. Fluid in finger or toe joints can escape through small holes. This can cause the skin to swell and create a cyst. These small holes may develop as the result of aging.

Mucous cysts are thin sacs that contain clear fluid. They are usually smooth or shiny in appearance and bluish-pink in color. The cysts can vary in size but are typically around 5–8 millimeters wide.

Mucous cysts are generally not associated with any symptoms other than the presence of the cyst itself. They can be uncomfortable, but, usually, they do not cause any pain.

Large, oral cysts may interfere with chewing or talking. It is also possible for a cyst to burst. This will cause the fluid to leak out, and it can become an infection risk.

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Usually, a visual and physical examination of the cyst is enough for a diagnosis. However, in some cases, a biopsy may be required.

Mucous cysts are straightforward to diagnose. A doctor will typically diagnose a cyst through a brief physical examination of the affected area.

In some cases, a biopsy may be needed to confirm the diagnosis. This procedure involves taking a small skin sample and examining it under a microscope. The analysis of this sample will help to determine whether a more serious condition is present, such as cancer or another type of growth.

Other possible tests include an ultrasound or a CT scan.

Treating a mucous cyst is often not necessary. In most cases, the cyst will heal on its own over time.

It is important not to pick at or pop the cyst. This can result in an open wound, which may become infected or cause permanent scarring. Over time, the cyst will burst itself as a part of the healing process.

Occasionally cleaning the cyst with salt water can help to prevent infection.

With oral mucous cysts, people should try to avoid biting or sucking on the lips or cheeks, as doing so can make them worse.

A person should see a doctor or a dentist if the cyst is causing discomfort or persists for longer than a couple of weeks. A doctor or dentist may use a sterile needle to burst the cyst manually.

It is also possible to remove the cyst by using:

  • Laser treatment. The cyst can be cut from the skin using a laser.
  • Cryotherapy. By freezing the cyst, it can be easily removed
  • Surgery. In more serious cases, the cyst can be surgically removed. The gland that caused the cyst is often taken out also.

Surgery is more common for cysts that have reoccurred several times.

Removing a mucous cyst is usually a safe procedure. In rare cases, the surrounding area can be injured during the process.

Mucous cysts are usually harmless and can be left alone. Often, they clear up within a couple of weeks. Picking at or popping cysts can slow down the healing process and increase the risk of infection.

It is advisable to see a doctor if a cyst is causing pain or discomfort, or it persists longer than normal. There are several options available for removing mucous cysts.