Seborrheic Keratosis

Seborrheic keratosis and actinic keratosis can resemble each other. They both begin to appear after the age of 40, and they both can appear crusty and scaly. It’s important to know the difference because actinic keratosis is more serious than seborrheic keratosis. Unlike seborrheic keratosis, actinic keratosis is caused by sun exposure, and it carries a small risk of turning into skin cancer (5% -10%).

Actinic keratoses vary in color, but they tend to be less pigmented than seborrheic keratoses. They can be flat or slightly raised, but tend to be flatter, and you might feel them before you see them. They feel scaly and rough, but may become more bumpy and wart-like over time, like seborrheic keratoses. They may also itch and bleed. They tend to appear in clusters in frequently sun-exposed areas.

How do you tell seborrheic keratosis from melanoma?

Seborrheic keratosis doesn’t turn into melanoma, but the two can be mistaken for each other. Both can be brown or black and appear anywhere on the body. There are some important differences, however:

• Seborrheic keratoses often appear in numbers, while melanoma is usually single.
• Seborrheic keratoses tend to have texture, while melanoma tends to be smooth.
• Seborrheic keratoses are well-defined, while melanoma can have a ragged or blurry border.
• Seborrheic keratoses are uniform, while melanoma may be asymmetrical or have more than one color.
• Seborrheic keratoses change little and slowly, while melanoma can grow and change quickly.

How is seborrheic keratosis diagnosed?

• Examination. Dermatologists can usually identify a seborrheic keratosis with the naked eye.
• Dermoscopy. If in doubt, your healthcare provider may look at the growth under a dermascope, a small, handheld lighted microscope.
• Biopsy.** **If your healthcare provider suspects any cancer, they will want to take a sample — or remove the whole growth — to examine in a lab.