Dark or black spots and patches appearing on the gums, known as gingival pigmentation, can be an alarming discovery. While healthy gum tissue is usually coral pink, variations in shade are common and often completely harmless. The causes of dark areas range widely from genetic predisposition and environmental factors to, in rare instances, a systemic health issue. Understanding the source of this discoloration is the first step toward determining if the change is merely cosmetic or requires medical attention.
Natural and Benign Pigmentation
The most frequent reason for dark or black gums is physiological melanin pigmentation. Melanin is the pigment that determines the color of skin, hair, and eyes, and its presence in the oral mucosa is genetically determined. This natural darkening is observed more often in individuals with darker skin tones, such as those of African, Asian, and Mediterranean descent.
This type of pigmentation typically appears as diffuse, uniform patches or bands of light brown to black color across the gum tissue. The color is generally symmetrical, often involving the entire attached gingiva, and does not alter the normal texture of the tissue. Since this pigmentation is not a sign of disease, no treatment is necessary unless the individual seeks a cosmetic change.
Isolated, small dark spots may also be caused by benign melanotic macules, which are comparable to freckles on the skin. These spots are usually flat, round or oval, and less than one centimeter in diameter. Benign melanocytic nevi, or moles, can also form on the gum tissue as small, well-defined brown or black lesions. While these spots are non-cancerous, any localized pigmented area that suddenly appears or changes size and shape should be evaluated by a dental professional.
Marks from Medications and Dental Procedures
Black or blue-gray spots on the gums may be caused by a dental procedure, resulting in an amalgam tattoo. These tattoos are localized discolorations that occur when small particles of silver amalgam filling material become embedded in the soft gum tissue. This happens during the placement, polishing, or removal of a dental filling, or when a tooth containing amalgam is extracted.
Amalgam tattoos are flat, painless, and appear as slate-gray, blue, or black macules, often near a tooth that has had a silver filling. While permanent, they are benign foreign body reactions. Dentists confirm the diagnosis by clinical appearance and dental history, sometimes using an X-ray if the metal particles are visible.
Certain prescription drugs can also cause the gums to darken as a side effect, known as drug-induced pigmentation. The antibiotic minocycline, frequently used for acne, is known to cause a diffuse blue-gray or grayish discoloration of the gums and other oral tissues. Other implicated medications include certain antimalarials and some drugs used in cancer therapy. This discoloration is not harmful and may resolve or lighten once the medication is stopped, though this requires medical supervision.
Tobacco use is another common environmental factor, leading to a condition called Smoker’s Melanosis. The chemicals in tobacco smoke stimulate the melanocytes in the gums to produce more melanin as a protective response. This typically presents as irregular, brownish-black patches, often more prominent on the gums near the front teeth. Cessation of smoking can sometimes lead to a partial or complete fading of this pigmentation over time.
Pigmentation Linked to Internal Health Issues
While most gum pigmentation is harmless, dark patches can occasionally signal an underlying systemic medical condition. One example is Addison’s disease, a rare endocrine disorder where the adrenal glands do not produce enough cortisol and aldosterone. The body compensates by increasing the release of a hormone that stimulates melanin production, leading to generalized hyperpigmentation.
This results in a diffuse, patchy, brownish-black discoloration affecting the skin and the mucous membranes of the mouth, including the gums. Oral pigmentation can sometimes appear before common systemic symptoms like fatigue, weight loss, and low blood pressure. The generalized and blotchy nature of the pigmentation, coupled with other non-specific symptoms, should prompt a full medical workup.
A separate, rare but serious cause is oral malignant melanoma, a form of cancer that appears as a dark spot on the gums. These lesions can initially mimic benign spots but are characterized by growth and change over time. Recognizing the warning signs is vital, using a modified version of the ABCDE rule:
- Asymmetry
- Border irregularity
- Color variation (shades of brown, black, blue, or red)
- Diameter (often larger than 6 millimeters)
- Evolving (any change in size, shape, color, or elevation)
Other genetic syndromes, such as Peutz-Jeghers syndrome, are also associated with oral pigmentation. This inherited disorder is characterized by the development of polyps in the gastrointestinal tract and distinctive mucocutaneous pigmentation. The spots are typically blue-black macules that appear around the lips, inside the mouth, and on the gums, often developing in childhood. While the spots are benign, the syndrome carries an increased risk of various cancers, necessitating regular medical surveillance.
The Importance of Professional Diagnosis
Because the appearance of dark spots on the gums can overlap between harmless variants and serious conditions, a professional evaluation is necessary. Only a dentist, periodontist, or oral pathologist can accurately determine the cause of the pigmentation. The diagnostic process begins with a thorough visual examination of the oral cavity and a review of the patient’s medical and dental history.
The clinician assesses the lesion’s size, color, borders, and whether the pigmentation is localized or diffuse. If a lesion cannot be definitively identified as benign based on clinical appearance or history, a biopsy is often performed. This procedure involves taking a small tissue sample for microscopic analysis, which provides the final and most accurate diagnosis. Consulting a professional ensures that any potentially serious issues are detected early, which is important for a favorable outcome.