Essential Info on Actinic Keratoses
Actinic keratoses (AKs) are premalignant lesions that appear on the skin in areas of chronic sun damage. They manifest as pink to red, scaly patches often described as ‘sandpapery’ growths that over time become increasingly more crusted and scab-like. AKs carry the real potential of evolving into squamous cell carcinoma, particularly as they enlarge.
They are often noted on the face, bald or balding scalp, ears, chest, arms, and hands. In patients who have more severe chronic sun damage, the lesions may be noted on the upper back, lower legs, and the tops of the feet.
These lesions are among the most frequently diagnosed conditions in all of dermatology. Given their known ability to transform into squamous cell carcinoma, dermatologists are always on the lookout for AKs.
Early Detection and Treatment Are Critical
Early detection and treatment of these lesions is an important responsibility for the dermatologist in our quest to minimize the need for more invasive surgical procedures—which may be indicated once full-blown squamous cell carcinoma has been diagnosed. When your dermatologist runs a palm over the sun exposed skin during your skin examination, it is quite likely that she/he is searching for these AKs, as they are often easier to identify by touch as opposed to visual inspection.
Treatment Options
Once identified, AKs can be treated with any one or more of several treatment options presently available.
Cryotherapy
Over the years, one of the mainstay treatments for actinic keratoses has been to treat the individual lesions with cryotherapy using liquid nitrogen.
This treatment delivers a frostbite-like injury to the lesions and they subsequently crust over and scab for about seven to ten days.
When the scab peels off, the treated area heals over with new skin that no longer shows the crusted sandpapery texture of the actinic keratosis.
When liquid nitrogen is sprayed onto the skin it feels like an intense “burning” sensation—this is because the liquid nitrogen is actually intensely cold.
This form of treatment is ideal for treatment of individual AK lesions.
Topical Agents
Other forms of treatment currently available include several topical agents with different mechanisms of action that are intended to achieve field treatment, clearing larger areas affected with multiple actinic keratoses:
5-fluorouracil: 5-fluorouracil is a topical chemotherapy medication that blocks DNA synthesis in the rapidly dividing sun-damaged cells, thereby destroying them. The medication may be applied once or twice daily for two to three weeks, based on the severity of the AKs.
Imiquimod: Imiquimod is a unique topical agent that works by activating certain cellular proteins in the immune system to heighten the immune response and launch an attack against the premalignant AKs.
Diclofenac Sodium: Diclofenac sodium is a non-steroidal cream that is suspected to work by inducing anti-inflammatory effects, although the exact mechanism of action against AKs is unknown.
Ingenol Mebutate: Ingenol Mebutate is derived from a plant extract and has the ability to induce rapid cell death of the abnormal, rapidly dividing cells of an AK. It also appears to have another mechanism of action by stimulating the immune system to attack AK lesions.
Photodynamic Therapy (PDT)
Photodynamic therapy (PDT) is a yet another form of treatment for AKs:
It involves sensitizing the affected skin with a chemical (Levulan) that accumulates in the abnormal cells of the lesion.
The affected skin is subsequently exposed to specific wavelengths of light, which triggers a chemical reaction that is deadly to the cells of the actinic keratoses.
Conventional PDT involves exposure of the skin primed with Levulan to blue light for 1,000 seconds (16 minutes and 40 seconds).
Daylight PDT involves a similar procedure, but the Levulan primed skin is exposed to daylight for two hours.
With conventional PDT, patients are expected to remain indoors for forty-eight hours after the treatment.
Surgical Options
Surgical options are available for the treatment of actinic keratoses, including shave removal or destruction of the lesions by electrodesiccation and curettage (a burning and scraping) procedure. These modalities are generally reserved for thicker lesions that are truly difficult to treat with less invasive procedures.
New Therapies on the Horizon
Other new therapies are currently under investigation, as we are still in search of an optimal treatment that clears the premalignant actinic keratosis lesions with a minimum of discomfort and inconvenience to the patient.
Prevention Rules
When they appear, actinic keratoses are a clear indication of significant preceding sun damage. Even though not every actinic keratosis develops into squamous cell skin cancer, it is not possible to predict which AKs will and which ones won’t. Once the skin is damaged by the sun, the effects of sunburns, even if they occurred many years before, are permanent.
This is the basis from which we recommend daily protection of the face with SPF 30+ sunblock or sunscreen containing moisturizer and SPF 50+ sunscreen for all exposed skin during more prolonged sun exposure. We firmly believe that it is never too late to start this practice of protecting the skin from the ravages of the sun.
Any questions? Consult one of our board-certified dermatologists. Please contact SSDP to schedule an appointment with any of our physicians.
