The darkening of gum tissue, known as gingival pigmentation, can be startling. While healthy gums are typically pink, variations in color, including shades of brown or black, are common and frequently harmless. Understanding the source of this discoloration is the first step, as causes range widely from genetics and lifestyle choices to, rarely, an underlying medical condition.
Natural Melanin Pigmentation
The most frequent and benign reason for dark gums is physiological pigmentation caused by melanin. Melanin is the natural pigment that provides color to the skin, hair, and eyes. Its presence in the gum tissue is a normal biological variation, similar to differing skin tones across the population.
This darkening is caused by melanocytes, the cells responsible for melanin production, located in the basal layer of the gingival epithelium. The amount of melanin produced is genetically determined and is often more pronounced in people of African, Asian, or Mediterranean ancestry. If the gums have always been a darker color, this is typically a stable condition requiring no medical intervention.
The pigmentation can present uniformly across the gum line or appear as patchy, diffuse areas of brown or black. Since this form of gingival darkening is not a disease, treatment is only considered for cosmetic reasons, such as for individuals with a “gummy smile” who are self-conscious about the color’s visibility.
Discoloration Caused by External Factors
Pigmentation can be introduced to the gum tissue from external sources, often related to lifestyle or dental procedures. One common external cause is Smoker’s Melanosis, a diffuse brown or black discoloration resulting from tobacco use. Nicotine and other compounds in smoke stimulate melanocytes to produce excess melanin, which acts as a protective mechanism against toxic substances.
The degree of Smoker’s Melanosis relates to the duration and amount of tobacco consumed, and the pigmentation is typically most evident on the lower front gums. This discoloration is often reversible, with dark patches slowly beginning to disappear between three months and three years after a person stops smoking.
Another localized external cause is the amalgam tattoo, which appears as a blue, gray, or black spot, usually near a tooth with a silver filling. This occurs when small fragments of dental amalgam become lodged in the soft gum tissue during a filling placement or removal. Amalgam tattoos are harmless and stable, generally requiring removal only if they are a cosmetic concern.
Medication-Induced Pigmentation
Certain medications can also induce gum darkening. These include the antibiotic minocycline, antimalarial drugs like chloroquine, and some chemotherapy agents. These drugs cause pigmentation either by stimulating melanin production or by depositing the drug’s metabolites directly into the mucosal tissue.
Dark Gums as a Sign of Systemic Disease
When gum darkening is not related to genetic factors or external exposures, it can occasionally signal an underlying health issue. A rare but serious cause is Addison’s disease, an endocrine disorder where the adrenal glands do not produce enough hormones like cortisol. This lack of feedback leads to an overproduction of adrenocorticotropic hormone (ACTH), which stimulates melanocytes to produce widespread pigmentation.
This dark pigmentation is typically diffuse and affects the skin as well as oral mucous membranes, including the gums, tongue, and lips. The presence of these blue-black or brown patches in the mouth can be one of the earliest signs of Addison’s disease, sometimes preceding other systemic symptoms.
A different, more acute cause of black or gray patches is Acute Necrotizing Ulcerative Gingivitis (ANUG), also known as “trench mouth.” This is a severe, painful gum infection characterized by the rapid destruction and death (necrosis) of tissue between the teeth. It presents as a gray or black pseudomembrane covering the ulcers. ANUG is caused by an overgrowth of oral bacteria, often triggered by factors such as severe stress, poor oral hygiene, smoking, or a compromised immune system.
Diagnosis and Treatment Options
When a patient presents with gum discoloration, diagnosis involves a thorough review of their medical history, including smoking habits and current medications. A clinical examination assesses the distribution, color, and texture of the pigmentation to differentiate between benign physiological causes and more concerning findings.
If the cause is unclear, or if the lesion is isolated, irregular, or has changed rapidly, further diagnostic procedures are necessary to rule out serious conditions like oral melanoma. This may involve a small tissue sample (biopsy) for microscopic analysis, or blood work to check for systemic issues like Addison’s disease.
Treatment depends entirely on the underlying cause. If a systemic disease like Addison’s is identified, managing the primary condition is the priority. For drug-induced pigmentation, switching to an alternative medication may reverse the discoloration. When the discoloration is benign, such as natural melanin pigmentation or an amalgam tattoo, treatment is elective and primarily for cosmetic improvement. Common cosmetic procedures for depigmentation include using a scalpel to surgically remove the top layer of pigmented tissue or employing laser therapy, which selectively destroys the melanin-producing cells.