Actinic keratosis, also known as a solar keratosis, is a scaly or crusty bump that arises on the skin surface. The base may be light or dark, tan, pink, red, a combination of these, or the same color as the skin. The scale or crust is horny, dry, and rough, and is often recognized by touch rather than sight. Occasionally, it itches or produces a pricking or tender sensation.
Actinic keratosis can be the first step in the development of skin cancer, and, therefore, is considered a precancerous skin condition. The presence of actinic keratoses indicates that sun damage has occurred and that any kind of skin cancer can develop. Actinic keratoses are precancerous (premalignant), which means they can develop into skin cancer. However, relatively few of them actually become cancers, a process that typically takes years. When a malignant change does occur, the cancer is called a squamous cell carcinoma.
When patients are diagnosed with this condition, they often say: " But I never go out in the sun!" The explanation is that it takes many years or even decades for these keratoses to develop. Typically, the predisposing sun exposure may have occurred many years ago. Short periods of sun exposure do not generally either produce AKs or transform them into skin cancers.
An actinic keratosis is a scaly or crusty bump that forms on the skin surface. They are also known as a solar keratosis. Dermatologists call them "AK's" for short. They range in size from as small as a pinhead to an inch across. They 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, and is often recognized easier by touch rather than sight. Occasionally it itches or produces a pricking or tender sensation, especially after being in the sun. It may disappear only to reappear later. Half of the keratosis will go away on their own if one avoid all sun for a few years. One often sees several actinic keratoses show up at the same time. A keratosis is most likely to appear on sun exposed areas: face, ears, bald scalp, neck, backs of hands and forearms, and lips. It tends to lie flat against the skin of the head and neck and be elevated on arms and hands.
Actinic keratosis is the most common sun-related growth. An estimated 60% of individuals older than 40 years who are predisposed have at least one actinic keratosis or solar keratosis. Usually, these people are fair-skinned, burn easily, and tan poorly, as well as have occupations or hobbies that result in excessive sun exposure. Many people have new actinic keratoses each year. They may be treated effectively by available methods. Actinic keratoses have the potential to develop into skin cancers; therefore, treatment is indicated.
Chronic sun exposure is the cause of almost all AKs. Sun damage to the skin accumulates over time, so that even a brief exposure adds to the lifetime total.
The likelihood of developing AK is highest in regions near the equator. However, regardless of climate, everyone is exposed to the sun. About 80 percent of solar UV rays can pass through clouds. These rays can also bounce off sand, snow, and other reflective surfaces, giving you extra exposure.
AKs can also appear on skin that has been frequently exposed to artificial sources of UV light (such as tanning devices). More rarely, they may be caused by extensive exposure to X-rays or specific industrial chemicals.
The treatment for actinic keratoses depends upon the number and size of the lesions. If the growths are small and show no signs of malignancy (cancer), they can be frozen with liquid nitrogen, called cryotherapy. Your doctor will want to recheck the growth areas at a later time to ensure the skin is clear. Patients with many AKs may be treated with photodynamic therapy. With this method, the doctor applies a chemical called aminolevulinic acid (ALA) to the skin. After it is absorbed, the doctor shines a special blue light onto the skin, which acts on the ALA solution in a way that destroys any cancerous cells. Over a short period of time, the AKs become crusty, and then heal. AKs may also be treated with a chemotherapy cream called 5-fluorouracil. When the lesions become red and crusty, application of the cream is stopped so the lesions can heal. Other promising treatments focus on stopping the gene mutations that cause AKs or altering the skin's immune system so it rejects the pre-cancerous cells.
Chemical peeling makes use of trichloroacetic acid (TCA) or a similar agent applied directly to the skin. The top skin layers slough off, usually replaced within seven days by new epidermis (the skin's outermost layer). This technique requires local anesthesia and can cause temporary discoloration and irritation.
A carbon dioxide or erbium YAG laser is focused onto the lesion, removing epidermis and different amounts of deeper skin. This finely controlled treatment is a good option for lesions in small or narrow areas; it can be particularly effective for keratoses on the face and scalp, as well as actinic cheilitis on the lips. However, local anesthesia may be necessary, and some pigment loss can occur.
PDT may be used to treat lesions on the face and scalp. Topical 5-aminolevulinic acid (5-ALA) is applied to the lesions by the physician. The next day, the medicated areas are exposed to strong light, which activates the 5-ALA. The treatment selectively destroys actinic keratoses, causing little damage to surrounding normal skin, although some swelling often occurs.