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Psoriasis vs. Skin Cancer

Reviewed by Debra Jaliman, MD on May 04, 2020

Psoriasis causes your body to make new skin cells too quickly. These cells tend to pile up and form spots, bumps, and thick, scaly patches.

Skin cancer, like all cancer, is the uncontrolled growth of faulty cells. They might start as spots on your skin and grow into clumps or “tumors.”

Most psoriasis is limited to the skin and is manageable with lifestyle changes and medication. Skin cancer, on the other hand, can spread to other parts of your body. It may be serious, even deadly, if you don’t find and treat it early.

There's no evidence that psoriasis makes you more likely to get skin cancer or vice versa. But it is sometimes possible to confuse cancerous spots with psoriasis.

Signs and Symptoms

Psoriasis most often shows itself as raised red patches, or “plaques.” These plaques don’t look anything like skin cancer.

But the plaques start with smaller spots, or “papules,” that grow together. They can also start with a single papule that gets bigger. You could mistake these smaller spots or dime-sized, raised, scaly circles for red, dry “sun spots” that are sometimes cancerous. These are called actinic keratoses.

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How to tell the difference? The first clue is location. Actinic keratoses mostly show up in sun-exposed areas of your skin, like your forehead, face, arms, and backs of your hands. Psoriasis is more common on your elbows, knees, and around your bellybutton. It can also happen on your scalp or in the crease of your behind.

Both kinds of spots can be raised and reddish. But actinic keratosis is rough and crusty. Psoriasis, though mostly dry, is usually soft -- unless you pick at it and it scabs over. Psoriasis also tends to flake off bits of skin, while actinic keratosis does not. If you have psoriasis, you might even notice little pieces around your home or work area.

Another clue is speed. A sudden outbreak of little red spots could be a type of psoriasis. They’re probably not actinic keratoses, which can take months or years to form.

Diagnosis

Skin conditions can be confusing. And you could have both psoriasis and cancerous spots like actinic keratoses at the same time. That's why it's important to inspect your body all over on a monthly basis, and tell your doctor about any new spots or growths. Only a full exam by your doctor can determine the cause of your skin symptoms.

Treatment

You treat psoriasis with creams and ointments. These usually have corticosteroids to reduce itching and swelling. Your doctor also may suggest UV light, which you can get from the sun or man-made light boxes.

Actinic keratoses normally peel off after your doctor freezes them with liquid nitrogen. Some anti-skin cancer creams may also make them disappear.

WebMD Medical Reference

Sources

SOURCES:

American Academy of Dermatology Association: “Psoriasis,”

Canadian Cancer Society: “How cancer starts, grows and spreads.”

Mary Spraker, MD, dermatologist, The Emory Clinic.

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