Elizabeth Pratt is a medical journalist based in Australia. She has a Master's degree in Health Communication and a Bachelor's degree in journalism. 

Kashif J. Piracha, MD, is board-certified in internal medicine and nephrology. He has an active clinical practice at Methodist Willowbrook Hospital in Houston, Texas.

A dark spot on the lip may appear for a variety of reasons. It may be due to sun exposure, vitamin deficiency, hormone-related issues, and even an excess of iron in the body. Sometimes, a dark spot can also be a skin cancer symptom, requiring immediate attention.

This article will discuss the causes of dark spots on the lips, diagnosis, treatment options, and when to see a healthcare provider.

A dark spot on the lips can be due to various causes. Some of these are harmless, and the spot can be faded with appropriate treatment. Other causes (like skin cancer) are more dangerous and require immediate attention.

Hyperpigmentation can cause dark spots or patches on the skin anywhere on the body. Among people with darker skin tones, hyperpigmentation is one of the most common reasons to see a dermatologist (a specialist in skin conditions).

Several factors can cause hyperpigmentation and dark spots. These include:

Hemochromatosis is a condition in which the body absorbs and stores an excessive amount of iron. This condition can cause problems like pain, fatigue, and problems with liver function. It can also cause issues with the skin.

In hemochromatosis, the skin can take on a bronze pigmentation from iron building up in the sweat glands. This can then cause a dark stain on the skin. Any existing scars may also be very pigmented.

Not drinking enough water can cause dry and chapped lips, leading to irritation. When lips are dry due to dehydration, it can be a common impulse to lick, pick or bite them. But this can make the lips more dry and irritated.

Constant irritation and inflammation caused by lip licking may cause post-inflammatory hyperpigmentation, causing dark spots on the lips.

Also known as age spots, these dark marks may occur in parts of the body that are exposed to the sun. Common areas for sunspots include the face or hands.

It is important to see a dermatologist to determine if a dark spot on the lip is a sunspot, as they can have a similar appearance to skin cancer. Mistakenly attempting to fade a spot that is actually skin cancer and not an age spot can cause more harm, as it gives the cancer time to grow and spread.

Angiokeratomas are dark lesions that appear on the skin, caused by the widening of the skin's capillaries (the smallest blood vessels). They are dark in color and may be reddish, blue, or purple. In people with darker skin tones, angiokeratomas may be less obvious.

Over time, the spots may look more like warts. They may also be associated with complications. These include:

In rare cases, a deficiency in vitamin B12 can cause hyperpigmentation. This may also be accompanied by many other symptoms of vitamin B12 deficiency.

In some cases, a deficiency in vitamin B12 can result in anemia. This can cause a variety of symptoms, including:

Among other complications, smoking can cause dark spots on the skin and lips. This is referred to as smoker's melanosis .

Smoking commonly causes pigmentation on the gums, palate, and lips, as well as other areas on the front of the body, like the face.

The thyroid is a gland found in the neck. It is responsible for producing hormones that regulate metabolism (the way your body produces and uses energy). Thyroid disorders can cause a variety of symptoms, including melasma .

Melasma can cause brown or blotchy patches of skin on the face. It is more common in females than in males.

Thyroid diseases can cause some signs on the skin. These include:

Marks on the skin that are caused by medications are referred to as drug-induced pigmentation.

Some of the types of drugs that can cause this include:

An allergic reaction can cause marks around the lips. The medical term for this is allergic contact cheilitis .

Common triggers for this include:

Skin cancer can take the form of a dark spot. Nonmelanoma skin cancer—cancer that does not begin in cells that produce pigmentation—can cause spots on the skin that may grow for months to years. They may also look like a sore that won't heal in three months.

Melanoma skin cancer can cause spots, lumps, or markings that may change color, shape, or size. Melanoma is a dangerous form of skin cancer that appears as a black or brown spot. While just 4% of skin cancers are melanoma, 79% of deaths related to skin cancer are due to melanoma.

Whenever you find a suspicious-looking spot on your skin, you should make an appointment with a dermatologist. A skin specialist can help determine if the spot is skin cancer or something else and treat it appropriately.

A dark spot on the skin could be due to various factors. For this reason, it is a good idea to consult with a dermatologist to receive an accurate diagnosis.

A dermatologist will examine the spot and consider whether it might be something serious like skin cancer. The only way to definitively diagnose skin cancer is through a skin biopsy. In this procedure, a sample of tissue is removed from the spot to be analyzed in the laboratory.

If not skin cancer, a dermatologist will be able to help identify other causes of a dark spot on the lip.

There are many possible causes of a dark spot on the lip, and treatment will vary based on the underlying cause.

Possible treatment options include, but are not limited to:

There are numerous potential causes for a dark spot on the lips. Some possible causes include skin cancer, a vitamin B12 deficiency, excessive iron in the body, thyroid disorders, smoking, age spots, and dehydration. The only way to get an accurate diagnosis is to see a specialist such as a dermatologist.

Treatment options will vary based on the underlying cause but may include lifestyle factors like improving hydration and changing personal hygiene products, medications, or medical procedures.

A dark spot on the lip may look annoying but can also be a sign of an underlying condition that requires attention.

Any time you are worried about a spot on your skin, you should consider making an appointment with a dermatologist. They will be able to help diagnose the cause of the mark and advise the best treatment option.

Dark spots on the lips can be due to a variety of causes. In some cases, hyperpigmentation will resolve within six to 12 months. But treatment will make this process faster. Dark spots caused by other conditions may require other treatments to resolve.

Any time you have a spot on your skin that is unusual or that concerns you, you should make an appointment with a dermatologist. A skin specialist will be able to help identify the cause of the mark as well as determine if it is skin cancer.

Hyperpigmentation is one example of a dark spot that will fade with proper treatment. If the dark mark is only a few shades darker than the rest of the skin, it may take six to 12 months to fade. If it is much darker, fading can take years. Appropriate treatment may speed up this process.

A dermatologist will be able to advise the best way to treat a dark spot on the lips and estimate how long it may take to fade.

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British Skin Foundation. Skin and genetic haemochromatosis.

American Academy of Dermatology Association. 7 dermatologists' tips for healing dry, chapped lips.

DermNet NZ. Lip licker’s dermatitis.

American Academy of Dermatology Association. What can get rid of age spots?

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Taghizadeh S, Dinçer Z, Marakoğlu İ. Smoker's melanosis: a case report. Tobacco Induced Diseases. 2018;16(3):121. doi:10.18332/tid/95192

American Academy of Dermatology Association. Thyroid disease: a checklist of skin, hair and nail changes.

Nahhas AF, Braunberger TL, Hamzavi IH. An update on drug-induced pigmentation. Am J Clin Dermatol. 2019;20(1):75-96. doi:10.1007/s40257-018-0393-2

Belluco PES, Belluco RZF, Reis CMS. Allergic contact cheilitis caused by propolis: case report. Einstein (Sao Paulo). 2022;20:eRC6151. doi:10.31744/einstein_journal/2022RC6151

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American Academy of Dermatology Association. How can I tell if I have skin cancer?

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