Actinic keratosis (AK) is a precancerous growth of the skin. AK results from a slow, uncontrolled growth of cells from the outermost layer of the skin, the epidermis. AKs are caused by long-term sun exposure.
AKs are usually found on sun-exposed skin, such as the face, forehead, cheek bones, eyebrows, nose, ears, lower lip, bald scalp, chest and upper back, forearm and backs of the hands, and lower legs and tops of the feet.
AKs are more common in older individuals with fair skin who experience excessive long-term sun exposure. However, AKs can be seen in younger individuals as early as 20 years old. It is important to know about AKs because, if left untreated, they may evolve into squamous cell carcinoma, a more aggressive type of skin cancer.
Anyone can get AK, but there are certain risk factors that make some individuals more susceptible to AK than others. Risk factors increase your susceptibility to AK; however, they do not mean you will develop AK.
Risk factors for AK include:
- Personal and family (genetic) history
- Fair skin with red hair and blue eyes
- Male over 50 years old
- Personal history of AK
- Personal history of a rare genetic syndrome, such as albinism or xeroderma pigmentosum
- Environmental exposure
- Excessive long-term sun and ultraviolet light exposure
- Fair skin and having grown up in a southern region
- Frequent exposure to outside work or recreation
- History of multiple sunburns
- Use of an indoor tanning lamp or bed
- Cigarette smoking
- History of radiation therapy
- Medical condition that suppresses the immune system, such as AIDS or medications that organ transplant recipients take to suppress their immune system
- Arsenic and tar exposure
- Excessive long-term sun and ultraviolet light exposure
What does AK look like?
Classic AK generally appears as a small, dry, scaly, rough patch of skin that can vary in size from a pencil eraser to a quarter. AKs can be red or skin colored or light brown and feel like sandpaper to the touch. Since AKs are often small and the same color as the surrounding skin, they are more easily felt than seen, sometimes being slightly tender or sore. There can be multiple AKs in the same area [Figure 1].
There are variants to a classic AK:
- Pigmented AK is slightly brown, often confused for freckles, and slightly rough to the touch [Figure 2]
- Hypertrophic AK becomes thicker, over months to years, with a hard scale, at times developing a horn-like growth [Figure 3]
- Actinic cheilitis is AK of the lip; usually the pink part of the lower lip will develop an area that feels dry, scaly, and chapped [Figure 4]
It is important to notice a sudden change or growth within AK, as it may signal the development of a squamous cell carcinoma, which is a more aggressive type of skin cancer.
How is AK diagnosed?
Inspection of your skin by your dermatologist can confirm whether or not a growth is suspicious for AK. AK doesn’t require a biopsy for diagnosis, but if a growth is suspicious for squamous cell carcinoma then a biopsy will be performed. This is a simple procedure performed in the office under local anesthesia. Your growth will then be sent to a pathology lab where thin sections from the growth will be examined under a microscope by a dermatopathologist (a dermatologist or a pathologist trained in the microscopic examination of skin lesions). In the event your biopsy confirms AK or squamous cell carcinoma, your dermatologist will discuss treatment options.
Inspection of your skin at home with a weekly skin self-exam can help you identify a spot or growth and help your dermatologist diagnose AK early. [Table 1] When inspecting your skin for any moles, growths, or spots, look for these signs.
New Changing Different and/or unusual
When inspecting your skin for any moles, growths, or spots, look for these signs.
When inspecting your skin for AK it is most helpful to pass your hand over your skin to feel for any rough spot, especially the skin on sun-exposed areas, such as the face, forehead, cheek bones, eyebrows, nose, ears, lower lip, bald scalp, chest and upper back, forearm and backs of the hands, and lower legs and tops of the feet. A new, rough, reddish spot may indicate the beginning of AK.
Be suspicious of any new spot or growth, changing spot or growth, or spot or growth that looks different or unusual from those in the surrounding area. If any spot or growth is suspicious, you should immediately report it to your dermatologist. Do not try to self-diagnose your condition.
There are many factors that can influence the choice of treatment:
- Type of AK
- Location, size, number, and aggressiveness of AK
- Patient’s general health
- Side effects, possible complications, benefits, and cure rate of a procedure
- Dermatologist’s experience and familiarity with a particular procedure
Each case is different. Your dermatologist will decide the most appropriate treatment plan for you.
Commonly used procedures to treat AK include:
- Topical chemotherapy
- Photodynamic therapy
For more information refer to “Common Procedures Performed in Dermatology”.
Patients diagnosed with AK should be examined by their dermatologist at least once a year. Remember, most individuals with a history of AK are more likely to develop another one. Your dermatologist will inspect your skin for any new AKs and will ensure that any previously treated AKs are not growing back.
Patients with a previous history of AK should also perform a weekly skin self-exam. Learning what AK looks like may help you identify a suspicious growth earlier. Inspecting the location of a previously treated AK may also help you identify an early recurrence of AK.
If you cannot see some part of your body, ask your partner or a family member to assist you with your weekly skin self-exam.