Due to an aging population, and the cumulative amount of time that most individuals have spent in the sun, it is estimated that more than 10 million Americans are living with actinic keratoses (AKs) on their skin. An actinic keratosis, also known as a solar keratosis, is a scaly or crusty growth that most commonly appears on the bald scalp, face, ears, lips, backs of the hands and forearms, shoulders, neck or any other areas of the body frequently exposed to the sun.
AKs typically begin as rough or sandpaper like lesions that are frequently recognized by feel rather than sight. Most often, AKs develop slowly but can reach sizes of a quarter of an inch or more. They can also disappear and reappear later. The more developed lesions usually will have a red appearance, but some will be light or dark tan, pink, or a combination of these. AKs will usually also have a hyperkeratotic, or thickened, scaly appearance on the skin. The incidence of AKs is slightly higher in men, and much more common in Caucasians when compared to African-Americans, Hispanics, Asians and other darker skinned individuals.
AKs can be the first step leading to squamous cell carcinoma (SCC) and are therefore known as precancers. Some studies suggest that 10% of AKs will progress to SCC. However some scientists in the medical community suggest that most if not all of AKs will turn malignant if given enough time to develop, and that AKs are just the earliest form of SCC. Ten percent may not sound very large, however the more AKs you have, the greater the chance that one or more may turn into skin cancer. SCC can be a serious form of skin cancer in that 2-10% of theses cancers spread to internal organs. More importantly, if you have actinic keratoses, it indicates that you have sustained sun damage and that you could develop any kind of skin cancer, not just SCC.
Recognizing AKs can be difficult for anyone not trained to diagnose and treat these lesions. You should examine your skin regularly, and if you find any unusual or changing growth, be suspicious and see a healthcare provider promptly. AKs will usually be skin lesions that are red, crusty, scaly, elevated, rough in texture, or may resemble warts. These lesions can also develop on lips, known as actinic cheilitis, and may have dried blood or horn-shaped scales on them.
Chronic ultraviolet (UV) radiation is the cause of AKs. UV radiation most commonly is from the sun; however tanning beds use the same UV radiation and is just if not more dangerous than the sun. UV radiation is cumulative, so even a brief exposure adds to the lifetime total. In addition, because this exposure is cumulative, older people are most likely to develop AKs. While some younger people can have AKs, most people presenting with AKs are above the age of 50.
Treating AKs is important toward preventing malignant skin cancers from developing. The most commonly used method for treating AKs is cryosurgery (freezing them with liquid nitrogen). The liquid nitrogen freezes the growths. Lesions subsequently become crusted and fall off. Topical medications, such as 5-flurouracil, imiquimod cream, and diclofenac all can be used to treat AKs. Topical medications, all FDA approved, have different mechanisms of action from each other. Another effective treatment for AKs is called photodynamic therapy (PDT) which involves applying a topical medication called 5-aminolevulinic acid (5-ALA) to the lesions. Subsequently, the medicated areas are exposed to a wavelength of light that activates the medication which in turn selectively destroys the abnormal cells, causing little damage to surrounding normal skin, although some redness and swelling usually occur. Chemical peeling and laser surgery can also be used to treat AKs.
Most healthcare providers will use a combination of treatment modalities because combination therapy can both improve the cure rates of AKs and reduce side effects. The best way to prevent AKs is to protect yourself from the sun. Some sun-safety habits to reduce cumulative sun damage from occurring include; seek shade, especially between 10 a.m and 4 p.m., do not burn and do use a sunscreen with an SPF of 30 or higher every day, and reapply after sweating or swimming. Cover up with clothing, including a wide-brimmed hat and UV-blocking sunglasses. Examine your skin from head-to-toe every month, and avoid all tanning salons. See your doctor annually for a professional skin exam.
Aaron Brasuell is the Physician’s Assistant with Northshore Dermatology and may be reached at 985-792-5959 or 985-641-5198