How to Tell the Difference Between Seborrheic Keratosis and Melanoma

Tips for identification

While seborrheic keratosis and melanoma share some similarities, there are also key differences to look out for.

Seborrheic keratosis

Seborrheic keratosis is more common in people with lighter skin tones. You’re also more likely to develop them as you get older.

Seborrheic keratosis usually appears on your:

• face
• chest
• shoulders
• back

Growths commonly:

• are round or oval shaped
• vary in size from very small to more than one inch across
• appear in groups of two or more
• are brown, black, or light tan in color
• have a waxy or scaly surface
• are slightly elevated above skin level

These growths often look like they’ve been pasted onto your skin, looking like a wart or skin tag. They generally aren’t painful or tender to the touch unless they’ve become irritated from rubbing or scratching against your clothing.

Melanoma

Melanoma also becomes more common as you age. In males, melanomas are more prevalent on the abdomen, back, head, and neck. Females are more likely to get melanomas on their legs.

The ABCDE rule can help you distinguish most melanoma growths from benign moles. The five letters of the acronym stand for the features to look for in a melanoma. If you notice any of these, you should speak with your doctor:

• Asymmetry: opposite sides of the mole don’t match in size or shape
• Border: a fuzzy border or ragged or blurred edges
• Color: a variety of colors within the same mole
• Diameter: moles larger than 1/4 inch, or growing over time
• Evolving: moles that change shape, color, or symptom, including redness, scaling, bleeding, or oozing

Are they caused by the same things?

Although melanomas and seborrheic keratosis can look similar, their causes are different.

Seborrheic keratosis

Researchers aren’t sure what causes seborrheic keratosis. It does seem to run in families, so genetics may be involved.

However, unlike melanoma, seborrheic keratosis doesn’t relate to sun exposure.

Melanoma

Overexposure to ultraviolet light (UV) from natural sunlight or tanning beds is a major cause of melanoma. The UV rays damage the DNA in your skin cells, leading them to become cancerous. However, with proper sun protection, this may be preventable.

Heredity also plays a role. You’re more likely to develop the disease if a doctor has previously diagnosed a parent or sibling with melanoma.

Still, only about 1 in 10 people diagnosed with melanoma also have a family member who has the disease. Most melanoma diagnoses relate back to sun exposure.

What’s the process of diagnosis?

Your dermatologist will likely begin by examining the surface characteristics of your growth with a magnifier.

Although there are visual differences between the two conditions, they can be misleading. Melanomas sometimes mimic features of seborrheic keratosis so successfully that misdiagnoses are possible. If there’s any doubt, your dermatologist will take a sample of your mole, known as a biopsy, and submit it to a laboratory for testing.

Newer diagnostic tests like reflectance confocal microscopy don’t require a skin sample. This type of optical biopsy uses a special microscope to perform a noninvasive examination.

What treatment options are available?

If you have moles or melanoma, your doctor will recommend treatment options.

Seborrheic keratosis

Seborrheic keratoses are often benign, so you’re fine to leave growths alone.

The one exception is when multiple spots appear suddenly. If this happens, it may be a sign of a tumor growing inside your body. Your doctor will test for any underlying conditions and work with you on any next steps.

Melanoma

Although melanoma accounts for about 1% of all skin cancers, it’s responsible for the majority of skin cancer-related deaths. If the melanoma is detected early on, surgical removal of the growth may be all that’s needed to remove the cancer from your body.

If a doctor discovers melanoma in a skin biopsy, you may need a surgical excision around the biopsy site to remove any possible additional cancerous tissue. Your doctor will use local anesthesia to numb the area before cutting into the skin. They’ll cut the tumor out, along with a small margin of healthy tissue surrounding it.

In some cases, melanoma can spread to the surrounding lymph nodes. Your doctor will biopsy the nearby nodes to determine whether they need to remove them along with the tumor and healthy skin sample. This procedure is known as dissection.

If the melanoma has spread to other organs (metastasized), your treatment will likely include other treatments like surgery, radiation, and immunotherapy.

Tips for prevention

Researchers have linked sun exposure to seborrheic keratosis and melanoma. The best way to reduce your risk for either condition is to stay away from tanning beds and be smart about sun protection.

You could:

• Apply sunscreen with an SPF of 30 or higher every day.
• If your skin is very fair or you have a family history of melanoma, use SPF 50 or higher.
• Reapply your sunscreen every 2 hours and immediately after sweating heavily or swimming.
• Avoid direct sunlight between 10 a.m. and 4 p.m., which is when the sun’s rays are most penetrating.
• Watch for changes in any existing moles. If you see anything unusual, schedule an appointment with your doctor.

The bottom line

Seborrheic keratosis is typically benign, so these growths shouldn’t impact your outlook or quality of life. If a medical professional diagnoses melanoma, they are your best resource for information about your individual outlook.

While there are ways to tell them apart, it’s always a good idea to get a doctor to check spots.