Actinic keratoses usually develop in areas that’ve been damaged by years of sun exposure. They form when you have actinic keratosis (AK), which is a very common skin condition.

AK occurs when skin cells called keratinocytes start to grow abnormally, forming scaly, discolored spots. The skin patches can be any of these colors:

• brown
• tan
• gray
• pink

They tend to appear on the parts of the body that get the most sun exposure, including the following:

• hands
• arms
• face
• scalp
• neck

Actinic keratoses aren’t cancerous themselves. However, they can progress to squamous cell carcinoma (SCC), though the likelihood is low.

When they’re left untreated, up to 10 percent of actinic keratoses can progress to SCC. SCC is the second most common type of skin cancer. Due to this risk, the spots should be regularly monitored by your doctor or dermatologist.

AK is primarily caused by long-term exposure to sunlight. You have a higher risk of developing this condition if you:

• are over age 60
• have light-colored skin and blue eyes
• have a tendency to sunburn easily
• have a history of sunburns earlier in life
• have been frequently exposed to the sun over your lifetime
• have human papilloma virus (HPV

Actinic keratoses start out as thick, scaly, crusty skin patches. These patches are usually about the size of a small pencil eraser. There might be itching or burning in the affected area.

Over time, the lesions can disappear, enlarge, remain the same, or develop into SCC. There’s no way of knowing which lesions may become cancerous. However, you should have your spots examined by a doctor promptly if you notice any of the following changes:

• hardening of the lesion
• inflammation
• rapid enlargement
• bleeding
• redness
• ulceration

Don’t panic if there are cancerous changes. SCC is relatively easy to diagnose and treat in its early stages.

Your doctor may be able to diagnose AK simply by looking at it. They may want to take a skin biopsy of any lesions that look suspicious. A skin biopsy is the only foolproof way to tell if lesions have changed into SCC.

AK may be treated in the following ways:

Excision

Excision involves cutting the lesion from the skin. Your doctor may choose to remove extra tissue around or under the lesion if there are concerns about skin cancer. Depending on the size of the incision, stitches may or may not be needed.

Cauterization

In cauterization, the lesion is burned with an electric current. This kills the affected skin cells.

Cryotherapy

Cryotherapy, also called cryosurgery, is a type of treatment in which the lesion is sprayed with a cryosurgery solution, such as liquid nitrogen. This freezes the cells upon contact and kills them. The lesion will scab over and fall off within a few days after the procedure.

Topical medical therapy

Certain topical treatments such as 5-fluorouracil (Carac, Efudex, Fluoroplex, Tolak) cause inflammation and destruction of the lesions. Other topical treatments include imiquimod(Aldara, Zyclara) and ingenol mebutate (Picato).

Phototherapy

• During phototherapy, a solution is applied over the lesion and the affected skin. The area is then exposed to intense laser light that targets and kills the cells. Common solutions used in phototherapy include prescription medications, such as aminolevulinic acid(Levulan Kerastick) and methyl aminolevulinate cream (Metvix).

How can you prevent actinic keratosis?

The best way to prevent AK is to reduce your exposure to sunlight. This will also help minimize your risk of skin cancer. Remember to do the following:

• Wear hats and shirts with long sleeves when you’re in bright sunlight.
• Avoid going outside at midday, when the sun is brightest.
• Avoid tanning beds.
• Always use sunscreen when you’re outside. It’s best to use a sunscreen with a sun protection factor (SPF) rating of at least 30. It should block both ultraviolet A (UVA) and ultraviolet B (UVB) light.

It’s also a good idea to examine your skin regularly. Look for the development of new skin growths or any changes in all existing:

• bumps
• birthmarks
• moles
• freckles

Make sure to check for new skin growths or changes in these places:

• face
• neck
• ears
• the tops and undersides of your arms and hands

Schedule an appointment with your doctor as soon as possible if you have any worrisome spots on your skin.