Actinic keratosis

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at April 26, 2016
StartDiseasesActinic keratosis

Found mainly on sun-exposed skin such as the face, ears, and back of hands, actinic keratosis is a scaly lesion that can develop into skin cancer if not treated. Getting actinic keratosis diagnosed and treated early is key to preventing more serious disease. Actinic keratosis is also called solar keratosis because it is caused by chronic over-exposure to the sun.


Definition & Facts

Actinic keratoses usually begin as a rough patch on skin that has been exposed to sun for decades. They progress to a defined lesion with scales that fall or scrape off. Found mainly on older adults, these lesions are precancerous and often are darker than the surrounding skin. They may have a reddish color due to proliferation of blood vessels in the area. It is very common in older Caucasian adults, especially those with fair skin and light colored eyes. However, people of all races and skin tones can get actinic keratosis.

Symptoms & Complaints

The main symptom of actinic keratosis is the sudden appearance of a rough patch or growth on the skin. These occur in very visible areas so people notice them quickly. The lesions soon begin producing yellow or white scales, which are caused by excess keratin production by rapidly dividing precancerous cells. Because it takes decades for the cellular changes in this lesion to develop, actinic keratosis usually presents in people who are middle-aged or elderly.

Actinic keratosis lesions may also develop a bumpy or wart-like appearance. An actinic keratosis may be itchy or tender, but they often are not. Most of these lesions are brown or tan in color, but they may be pink, red, or the same color as surrounding skin. In most cases, people notice them quickly because they are located in highly visible areas such as the face.


The majority of actinic keratoses are caused by long term exposure to ultraviolet light, or UV light. This usually occurs over decades of normal sun exposure. This is the reason that these lesions arise only in areas that are exposed to sunlight on a daily basis. However, sunlight is not the only culprit. Some people develop actinic keratosis after long term exposure to UV light in tanning beds or in jobs where UV light is commonly used.

In addition, people who get PUVA therapy for psoriasis or other skin disorders are at high risk of developing actinic keratosis because these therapies also involve UV exposure. There may be a genetic component to actinic keratosis as well. Some families have a higher incidence of this lesion than other families, which suggests that there may be genetic differences that influence susceptibility.

Diagnosis & Tests

Most physicians can diagnose actinic keratosis with a simple examination because it is so common and has distinctive features. However, doctors usually will do a biopsy so they know whether the cells have begun to undergo cancerous changes. The doctor will give a numbing injection and then take a sample of the actinic keratosis so a lab can look at the cells in the lesion.

This may be a punch biopsy, in which a tiny circle of skin is punched out from the center of the lesion, or a shave biopsy, in which the entire lesion is carefully shaved off the skin with a sharp blade. Most doctors prefer a punch biopsy initially if the lesion is located on the face or scalp, to reduce the amount of scarring. These biopsies heal quickly and do not leave a noticeable scar.

If the lesion is on the back of the hand or another less visible area, the doctor may choose to remove the entire lesion so its borders can be checked carefully. Once the biopsy has been taken, a laboratory will freeze the sample and slice it into very thin slices so the cells can be looked at in detail. When the doctor gets the results of the biopsy, he or she can develop a treatment plan.

Treatment & Therapy

There are several options for treatment of actinic keratosis. If a person has only a few lesions, doctors often prefer to remove the lesions entirely. This can be done with cryotherapy or scraping. Cryotherapy is the most common treatment for this lesion. In cryotherapy, the doctor will apply a very cold liquid to the lesions. This liquid will completely kill the cells to which it is applied. Over a few days, the damaged cells of the lesion will peel off, leaving healthy skin underneath.

In scraping, a sharp blade will be used to remove the entire lesion. A lab will then look at the scraping to ensure that the entire lesion was removed. Both of these options can leave scarring; however, because actinic keratosis can become squamous cell carcinoma, it is important to completely remove it.

If there are many lesions, doctors will use topical medications that target abnormal cells, such as fluorouracil or diclofenac. These topical medications will kill most actinic keratosis cells without leaving scarring, although they are not as effective as a simple lesion removal. Doctors may choose to remove any remaining lesions that did not respond to topical treatments.

Prevention & Prophylaxis

The best way to prevent actinic keratosis and other skin lesions resulting from UV light is to avoid chronic sun exposure. Wear sunscreen on a daily basis on areas that cannot be covered effectively by clothing. In addition, avoid tanning beds and other artificial sources of UV light. Even getting a light tan occasionally throughout your life can lead to actinic keratosis in old age.

Because actinic keratosis is a precancerous lesion, it is important to identify and treat it as early as possible. Go to a doctor whenever you see any changes in your skin so these lesions can be treated and removed before they cause a deadly illness such as cancer.