Actinic Keratosis

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

Types & Stages

Actinic keratoses could be categorized into seven subtypes: 

• Hypertrophic. Characterized by thick, scaly, and sometimes warty growths. 
   
• Atrophic. Thin, flat and scaly patches. 
   
• Bowenoid. Usually a red, scaly patch that resembles Bowen's disease, a type of squamous cell carcinoma in situ, meaning it’s only on the outer layer of the skin. 
   
• Acantholytic. Shows separation of skin cells.
   
• Epidermolytic. Features changes in the outer layer of the skin.
   
• Lichenoid. Resembles lichen planus, a condition of the skin, hair, nails, mouth and genitals. On skin, lichen planus often appears as purple, itchy, flat bumps that develop over several weeks. In the mouth and genital mucosa, lichen planus forms lacy white patches, sometimes with painful sores.
   
• Pigmented. Brown or dark patches

Signs & Symptoms

Actinic keratoses vary in appearance. 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

Diagnosis

Your doctor will likely be able to determine whether you have an actinic keratosis simply by looking at your skin. If there's any doubt, they may do other tests, such as a skin biopsy.

• Skin biopsy. A small sample of skin is taken for analysis in a lab. A biopsy can usually be done in a clinic after a numbing injection. These include:
   
  • Punch biopsy. For this, a tool that looks like a tiny round cookie cutter is used to remove a deeper sample of skin. Your doctor rotates the punch biopsy tool on the skin until it cuts through all the layers. The sample is then removed, and the edges of the biopsy site are stitched together.
     
  • Shave biopsy. This biopsy procedure, also known as saucerization, shaves off the top layers of the skin with a small surgical blade. Any bleeding is then stopped by putting either an ointment or a chemical that stops bleeding on it, or by using a small electrical current to seal (cauterize) the wound.

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.

Treatment

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

Treatments include: 

• Medicines. If you have several actinic keratoses, your doctor might prescribe a medicated cream or gel to remove them. These products might cause inflamed skin, scaling or a burning sensation for a few weeks.
   
• Surgical and other procedures. If your doctor recommends removing them, there are several methods.
   
  • Freezing (cryotherapy). They can be removed by freezing them with liquid nitrogen. Your health care provider 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 health care provider's office. 
     
  • 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 a pencil-shaped instrument is used to cut and destroy the affected tissue with an electric current. This procedure requires local anesthesia. 
     
  • 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.
  • 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. 

Causes & Risk Factors

Anyone can develop actinic keratoses, but these factors can increase your risk: 

• Ultraviolet (UV) exposure. A history of unprotected exposure to ultraviolet (UV) radiation from the sun or indoor tanning. This includes people who work outdoors in the sun, people with a bald scalp or thinning hair and those who have had sunburns.
   
• Geographic location. The closer to the equator you live, the more likely you are to have AKs.
   
• Weakened immune system. Due to a medical condition or medications.
   
• Light skin. AKs occur far more frequently in people with light skin, especially if you tend to freckle or get sunburns. 
   
• Age. AKs are most common in people age 40 and older.

Screening

With skin self-exams and skin checks by a health care professional like a dermatologist actinic keratoses can often be found early. When skin cancers are found early, they are likely to be easier to treat.