Actinic Keratosis and Treatment
What is Actinic Keratosis?
An actinic keratosis is a scaly or crusty bump that forms on the skin surface. They are also called solar keratosis or sun spots. They range in size from as small as a pinhead to over an inch across. Actinic keratoses may be light or dark, tan, pink, red, a combination of these, or the same color as ones skin. The scale or crust is horn-like, dry, and rough. In the beginning, actinic keratoses are frequently so small that they are recognized by touch rather than sight. It feels as if you were running a finger over sandpaper.
Occasionally actinic keratoses itch or produce a pricking or tender sensation, especially after being in the sun. They may disappear only to reappear later. Keratoses are most likely to appear on sun exposed areas: face, ears, bald scalp, neck, backs of hands and forearms, and lips.
Why is it dangerous? Actinic keratosis can be the first step in the development of skin cancer, and, therefore, is a precursor of cancer. It is estimated that 10 to 15 percent of active lesions, which are redder and more tender than the rest will take the next step and progress to squamous cell carcinomas. These cancers are usually not life threatening, provided they are detected and treated in the early stages. However, if this is not done, they can bleed, ulcerate, become infected, or grow large and invade the surrounding tissues and, 3% of the time, will metastasize or spread to the internal organs.
Chronic sun exposure is the cause of almost all actinic keratoses. Sun damage to the skin is cumulative, so even a brief period in the sun adds to the lifetime total. Cloudy days are not safe either, because 70-80 percent of solar ultraviolet (UV) rays can pass through clouds. These harmful rays can also bounce off sand, snow and other reflective surfaces, giving you extra exposure. In addition, the ultraviolet radiation given off by the lamps in a tanning salon can be even more dangerous than the sun.
What is Cryotherapy?
Cyrosurgery refers to use of a cryogen to lower the temperature of the skin and produce cell death. The most common cryogen is liquid nitrogen, with a temperature of -195.8°C. Keratinocytes, the outer most layer of human skin, die when exposed to approximately -40 to -50°C. Other structures in the skin, such as collagen, blood vessels, and nerves, are the most resistant to the lethal effects of cold than keratinocytes. Melanocytes, the cells responsible for skin pigmentation, are more sensitive than keratinocytes; thus cryosurgery often leaves white spots.
Cryosurgery is best for treating thin, well-demarcated lesions and can be used to treat solitary lesions or small numbers of scattered lesions. Hyperkeratotic lesions are more resistant to cryosurgery and should be debrided before treatment using a scalpel or curette.
An extremely cold substance, such as liquid nitrogen, is applied to skin lesions. The substance freezes the skin surface, causing blistering or peeling. As your skin heals, the lesions slough off, allowing new skin to appear. This is the most common treatment, takes only a few minutes, and can be performed in your doctor’s office.
Potential adverse effects of cryotherapy include infection, hypo/hyperpigmentation, scarring, and hair loss. Patients should know that they will experience some pain at the time of the freezing, but local anesthesia is not required.
What to Expect?
Redness, swelling, and the formation of a blister at the site of cryotherapy are all expected results of the treatment. A gauze dressing is applied and patients should wash the site two to three times a day. In addition, the patient should apply triple antibiotic ointment daily while fluid continues to ooze from the wound, usually for 5-14 days. A dry crust then forms that falls off by itself.
Healing time can vary by the site treated and the cryotherapy technique used. Wounds on the head and neck may take four to six weeks to heal, but those on the body, arms, and legs can take longer. Some patients experience pain at the site following the treatment. This can usually be eased with acetaminophen (Tylenol), though in some cases a stronger pain reliever may be required.
Cryotherapy boasts high success rates in permanently removing skin growths; even for malignant lesions such as squamous cell and basal cell cancers, studies have shown a cure rate of up to 98%.
Several topical therapies are available for the treatment of actinic keratosis including Efudex and Aldara. Topical therapies are useful for patients with more than 15 actinic keratoses. The anatomic location of the lesions impacts the response time to topical treatments. Actinic keratoses on the face respond the quickest (more quickly than those on the scalp), whereas lesions on the arms usually take the longest to respond. After topical treatment, actinic keratoses may reoccur on the treated area. Patients must avoid sun exposure during treatment.
Efudex 5% Cream is recommended for the topical treatment of multiple actinic keratoses. Efudex is the only topical treatment approved by the FDA to be used on the face, scalp, hands, arms, shoulders, and trunk.
Mechanism of Action
Actinic keratoses multiply at a faster rate than normal cells. Fluorouracil interferes with a cell’s ability to reproduce. As a result, the unhealthy cells absorb the fluorouracil faster than healthy, normal cells causing unbalanced growth and death of the cell.
Twice a day for 3 weeks
Early inflammatory phase (week 1)
Inflammatory phase (weeks 2-3)
The areas of the skin affected by AK lesions will turn red and look/feel irritated; a sign that elimination of unhealthy cells is occurring. This stage of treatment is unattractive and uncomfortable. Areas of skin where there were no lesions may become red and inflamed. This is because abnormal cells can become inflamed even if the cells were not previously noticeable on the skin’s surface.
Tumor disintegration phase
The lesions resolve as the skin exfoliates
Over 1-2 weeks, new skin grows into the treatment area
Efudex is not likely to leave scars or cause hypopigmentation. Many patients have reported that the skin is smoother with a more even tone after treatment
Aldara Cream is indicated for topical treatment of nonhyperkeratotic AK on the face or scalp (not concurrently) in immunocompetent adults.
Mechanism of Action
Aldara Ceram works from within by activating the body’s own immune system. When applied to the skin, immune cells are activated and travel to the area to eliminate abnormal cells. However, the MOA for treating AK is unknown.
Aldara Cream is used once a day before bedtime for 2 days a week, 3-4 days apart (ex Mon/Thurs or Tues/Fri). It is left on the skin for 8 hours and washed off. Treatment should continue for 16 weeks.
Include redness, swelling, itching, flaking, or scabbing a or around the application site. Using too much, too often, and too long can increase the chances of having a severe skin reaction.