An actinic keratosis (ak-TIN-ik ker-uh-TOE-sis) is a rough, scaly patch on the skin that develops from years of sun exposure. It's often found on the face, lips, ears, forearms, scalp, neck or back of the hands.

Also known as a solar keratosis, an actinic keratosis grows slowly and usually first appears in people over 40. You can reduce your risk of this skin condition by minimizing your sun exposure and protecting your skin from ultraviolet (UV) rays.

Left untreated, the risk of actinic keratoses turning into a type of skin cancer called squamous cell carcinoma is about 5% to 10%.

Actinic keratoses vary in appearance. Signs and symptoms include:

• Rough, dry or scaly patch of skin, usually less than 1 inch (2.5 centimeters) in diameter
• Flat to slightly raised patch or bump on the top layer of skin
• In some cases, a hard, wartlike surface
• Color variations, including pink, red or brown
• Itching, burning, bleeding or crusting
• New patches or bumps on sun-exposed areas of the head, neck, hands and forearms

When to see a doctor

It can be difficult to distinguish between noncancerous spots and cancerous ones. So it's best to have new skin changes evaluated by a doctor — especially if a scaly spot or patch persists, grows or bleeds.

An actinic keratosis is caused by frequent or intense exposure to UV rays from the sun or tanning beds.

Anyone can develop actinic keratoses. But you're at increased risk if you:

• Have red or blond hair and blue or light-colored eyes
• Have a history of a lot of sun exposure or sunburn
• Tend to freckle or burn when exposed to sunlight
• Are older than 40
• Live in a sunny place
• Work outdoors
• Have a weakened immune system

If treated early, actinic keratosis can be cleared up or removed. If left untreated, some of these spots might progress to squamous cell carcinoma — a type of cancer that usually isn't life-threatening if detected and treated early.

Sun safety is necessary to help prevent development and recurrence of actinic keratosis patches and spots.

Take these steps to protect your skin from the sun:

• Limit your time in the sun. Especially avoid time in the sun between 10 a.m. and 2 p.m. And avoid staying in the sun so long that you get a sunburn or a suntan.

• Use sunscreen. Before spending time outdoors, even on cloud days, apply a broad-spectrum water-resistant sunscreen with a sun protection factor (SPF) of at least 30, as the American Academy of Dermatology recommends.

  Use sunscreen on all exposed skin, and use lip balm with sunscreen on your lips. Apply sunscreen at least 15 minutes before going outside and reapply it every two hours — or more often if you're swimming or perspiring.

  Sunscreen is not recommended for babies under 6 months. Rather, keep them out of the sun if possible, or protect them with shade, hats, and clothing that covers the arms and legs.

• Cover up. For extra protection from the sun, wear tightly woven clothing that covers your arms and legs. Also wear a broad-brimmed hat, which provides more protection than does a baseball cap or golf visor.
• Avoid tanning beds. The UV exposure from a tanning bed can cause just as much skin damage as a tan acquired from the sun.
• Check your skin regularly and report changes to your doctor. Examine your skin regularly, looking for the development of new skin growths or changes in existing moles, freckles, bumps and birthmarks. With the help of mirrors, check your face, neck, ears and scalp. Examine the tops and undersides of your arms and hands.

Your doctor will likely be able to determine whether you have an actinic keratosis simply by examining your skin. If there's any doubt, your doctor may do other tests, such as a skin biopsy. During a skin biopsy, your doctor takes a small sample of your skin for analysis in a lab. A biopsy can usually be done in a doctor's office after a numbing injection.

Even after treatment for actinic keratosis, your doctor might suggest that you have your skin checked at least once a year for signs of skin cancer.

An actinic keratosis sometimes disappears on its own but might return after more sun exposure. It's hard to tell which actinic keratoses will develop into skin cancer, so they're usually removed as a precaution.

Medications

If you have several actinic keratoses, your doctor might prescribe a medicated cream or gel to remove them, such as fluorouracil (Carac, Fluoroplex, others), imiquimod (Aldara, Zyclara), ingenol mebutate or diclofenac (Solaraze). These products might cause redness, scaling or a burning sensation for a few weeks.

Surgical and other procedures

Many methods are used to remove actinic keratosis, including:

• Freezing (cryotherapy). Actinic keratoses can be removed by freezing them with liquid nitrogen. Your doctor applies the substance to the affected skin, which causes blistering or peeling. As your skin heals, the damaged cells slough off, allowing new skin to appear. Cryotherapy is the most common treatment. It takes only a few minutes and can be done in your doctor's office. Side effects may include blisters, scarring, changes to skin texture, infection and changes in skin color of the affected area.
• Scraping (curettage). In this procedure, your doctor uses a device called a curet to scrape off damaged cells. Scraping may be followed by electrosurgery, in which the doctor uses a pencil-shaped instrument to cut and destroy the affected tissue with an electric current. This procedure requires local anesthesia. Side effects may include infection, scarring and changes in skin color of the affected area.
• Laser therapy. This technique is increasingly used to treat actinic keratosis. Your doctor uses an ablative laser device to destroy the patch, allowing new skin to appear. Side effects may include scarring and discoloration of the affected skin.
• Photodynamic therapy. Your doctor might apply a light-sensitive chemical solution to the affected skin and then expose it to a special light that will destroy the actinic keratosis. Side effects may include redness, swelling and a burning sensation during therapy.

You're likely to start by seeing your family doctor or primary care doctor. In some cases when you call to set up an appointment, you may be referred directly to a specialist in skin diseases (dermatologist).

What you can do

Your time with your doctor is limited, so preparing a list of questions will help you make the most of your appointment. For actinic keratoses, some basic questions to ask your doctor include:

• Are tests needed to confirm the diagnosis?
• What are my treatment options and the pros and cons of each?
• What will the treatments cost? Does medical insurance cover these costs?
• What suspicious changes in my skin should I look for?
• What kind of follow-up should I expect?

What to expect from your doctor

Questions your doctor may ask you include:

• When did you first notice the patches or spots?
• Have you noticed multiple patches or spots?
• Have you noticed any changes in the appearance of the affected skin?
• Is the condition bothersome?
• Have you experienced frequent or severe sunburns?
• How often are you exposed to sun or UV radiation?
• Do you regularly protect your skin from UV radiation?