Black spots inside the cheek can have several causes. These include blisters or hyperpigmentation. In rare cases, they may indicate something more serious, such as mouth cancer.

Many harmless conditions can cause a black spot to develop inside the cheek. Often, there will be no other symptoms, and it will improve without treatment.

Rarely, however, a black spot inside the cheek may be a symptom of oral melanoma. This is a rare type of cancer.

The American Cancer Society estimate that just over 54,000 people will develop mouth or throat cancer in 2021. Melanoma usually accounts for 0.5% of all oral cancers.

This article will examine some potential causes of a black spot inside the cheek. It will also look at some treatment options and when a person should contact their doctor.

Blisters are raised bubbles on the skin with fluid inside. They can occur anywhere on the body, including in the mouth.

Blood blisters contain blood and appear dark red or purple. They may develop in the mouth due to accidentally biting the cheek or as a result of an allergic reaction.

Learn more about blood blisters in the mouth here.


Blood blisters are not typically harmful, and they will often heal without treatment.

Sometimes, however, they may cause pain or discomfort. In these cases, a person can use over-the-counter (OTC) pain relief medication.

Amalgam tattoos occur when metal fillings leak, causing dark marks to appear inside the mouth.

These marks can appear when a dentist places or removes a filling and tiny metal fragments fall between the teeth.

They most commonly appear on the gum or cheek, near the amalgam filling. However, they can appear anywhere in the mouth.


Amalgam tattoos do not cause any symptoms or require any form of treatment.

Smoking can cause smoker’s melanosis. This is a condition wherein brown or black pigmentation develops inside the mouth and throat.


This condition is not harmful, and it does not require treatment.

However, the tobacco smoke that causes these spots is harmful to various areas of the body. For example, smoking can cause gum disease, tooth loss, and mouth cancer, as well as several other conditions.

Melanoma is a cancer of the pigment-making cells, or melanocytes, that typically affects the skin. However, these cancers can also occur on mucosal membranes, such as in the mouth.

Oral melanoma usually appears as a raised area that has a black, brown, or dark blue appearance. These marks can be asymmetric with an irregular border.

There may also be swelling, if inflammation is present.

One 2020 article notes that oral melanoma is not related to sun exposure. Healthcare professionals are unsure about what the risk factors may be, but they may include:

  • dental irritation
  • cigarette smoking
  • alcohol consumption


The main treatment option for oral melanoma is surgery. A healthcare professional may also recommend radiation therapy.

Addison’s disease is an endocrine disorder that occurs when the adrenal glands, which are the glands on the top of the kidneys, do not make enough of certain hormones. These include cortisol and aldosterone.

The National Institute of Diabetes and Digestive and Kidney Diseases note that Addison’s disease can cause the development of darker areas on the skin and inside the mouth.

Other symptoms can include:

  • chronic fatigue
  • muscle weakness
  • abdominal pain
  • weight loss
  • appetite loss


Treatment for Addison’s disease will include hormone replacement medications. People can take a corticosteroid, such as hydrocortisone, to replace missing cortisol. They will take an oral tablet two or three times per day.

To replace aldosterone, a person can take fludrocortisone to help balance the amount of fluid and sodium in the body.

Peutz-Jeghers syndrome is a rare genetic condition that causes dark freckles to appear around the face and inside the mouth. It may also cause mushroom-shaped tissue growths called polyps to develop throughout the gastrointestinal tract.

Peutz-Jeghers syndrome can also cause other symptoms, including:

  • nausea
  • vomiting
  • stomach pain
  • rectal bleeding
  • digestive issues


There is currently no cure for Peutz-Jeghers syndrome. However, treatments may involve surgically removing any polyps that are causing gastrointestinal problems.

A doctor or dentist will perform a physical examination of the black spots to determine the cause. Also, they will likely ask the person whether or not the spots are painful or have any accompanying symptoms.

A doctor may also check a person’s medical history for any signs of genetic conditions, such as Peutz-Jeghers syndrome, that could be the cause. They might also review the person’s dental records for the presence of metal fillings.

Depending on their assessment, a doctor may also order additional tests to make a firm diagnosis. For example, they might require a blood test or skin sample for further analysis.

Many causes of black spots inside the cheek, such as amalgam tattoos, are harmless.

Although no medical treatment is necessary for some causes of a black spot in the cheek, a person should contact a doctor about any sore or spot that lasts for longer than 3 weeks.

If the black areas develop sores or ulcers, these could be symptoms of mouth cancer. Early detection of mouth cancer is crucial for successful treatment.

There are many possible causes of black spots inside the cheek. For most people, these spots will cause no additional symptoms and will not require treatment.

Some people may require OTC treatments for causes that cause pain, such as blood blisters. Other causes, such as mouth cancer, will require medical treatment.

Although black spots inside the mouth may be harmless, it is worth contacting a doctor about persistent cases. They can help determine whether the spot is harmless or requires further care.