Dark spots on the gums, known as gingival hyperpigmentation, can be startling to notice, but they are often a harmless phenomenon. This discoloration occurs when there is an increase in the pigment melanin within the gum tissue, leading to patches of brown, gray, or black. While the appearance of a new or changing spot may cause concern, most instances are benign and represent minor cosmetic variations. Understanding the different origins of these spots can provide clarity on when they are simply a part of your natural biology and when they might warrant a professional evaluation.
Common, Harmless Pigmentation
The most frequent source of dark spots is physiological pigmentation, which is genetically determined and analogous to skin tone. This natural variation results from melanocytes, the cells responsible for producing the brown pigment melanin, being more active in the gum tissue. This type of pigmentation is often diffuse and symmetrical, appearing across the gums, and is more prevalent in individuals with darker skin tones.
Another common cause is Smoker’s Melanosis, a brown or black pigmentation that develops in response to tobacco use. Chemicals in cigarette smoke stimulate the melanocytes in the oral mucosa to produce excess melanin, serving as a protective reaction. This pigmentation is usually seen on the lower front gums and may fade gradually once a person stops using tobacco products.
Small, localized blue, gray, or black spots known as amalgam tattoos are also frequently encountered in dental examinations. These spots are caused by tiny fragments of silver dental filling material—an alloy of metals like silver, tin, and copper—that accidentally become embedded in the gum tissue during a dental procedure. Amalgam tattoos are permanent, painless, and flat, typically appearing near a tooth that has or once had a metallic restoration.
Spots Caused by Medications and Systemic Conditions
Pigmentation can also be a side effect of certain medications, where the drug or its metabolites deposit in the oral tissues, creating a bluish-black discoloration. The antibiotic Minocycline, often used for long-term acne treatment, is a well-known culprit for inducing pigmentation in the gums and other areas. This drug-induced pigmentation is generally not harmful and may slowly decrease after the medication is discontinued, though it can sometimes be permanent.
Specific antimalarial drugs and certain chemotherapy agents have also been documented to cause oral hyperpigmentation. This type of discoloration is usually a generalized change in color rather than a single distinct spot, differentiating it from localized causes like amalgam tattoos.
In rare instances, dark spots on the gums can be a manifestation of an underlying systemic health issue. Addison’s disease, an endocrine disorder involving insufficient hormone production by the adrenal glands, can cause diffuse, patchy pigmentation on the oral mucosa. Peutz-Jeghers syndrome, a rare genetic condition, is characterized by small, brown to blue-gray spots on the lips and oral mucosa, including the gums.
Signs That Require Immediate Evaluation
While most dark spots are benign, a small number can signal a serious condition, such as oral melanoma, a rare but aggressive form of cancer. A change in a spot that was previously stable is the most significant warning sign. Clinicians use the “ABCDE” criteria to assess suspicious pigmented lesions.
ABCDE Criteria
- Asymmetry means the spot is not uniform, and one half does not match the other.
- Border irregularity refers to uneven, notched, or scalloped edges instead of a smooth outline.
- Color variation is a concern if the spot contains multiple colors, such as shades of brown, black, blue, or red.
- Diameter greater than 6 millimeters, roughly the size of a pencil eraser, is a common feature of melanoma.
- Evolving is the most important criterion, referring to any change in size, shape, color, or elevation over time.
Any dark spot that is new, rapidly changing, or is accompanied by symptoms like bleeding, pain, or a persistent sore that does not heal warrants an immediate visit to a dental professional or doctor.