Actinic Keratosis: Symptoms, Causes, and Treatment in Florida

Actinic keratosis (also called solar keratosis) is one of the most common precancerous skin lesions in the United States, affecting around 40 million Americans each year. These rough, scaly patches develop after years of cumulative sun exposure and most often appear on areas of the body most exposed to UV radiation, such as the face, scalp, ears, and forearms.

While an individual actinic keratosis is not yet cancer, it is considered precancerous because a small percentage of lesions can progress into squamous cell carcinoma if left untreated. That’s why dermatologists consider actinic keratoses among the most important precancerous skin lesions to identify and treat early. At Suncoast Skin Solutions, our board-certified dermatologists diagnose and treat actinic keratosis before it progresses. 

What Does Actinic Keratosis Look Like?

Actinic keratoses can vary in appearance, but most share a distinctive set of visual and tactile characteristics, including: 

• A rough, dry, or scaly patch of skin, usually smaller than one inch in diameter
• Flat to slightly raised pink, red, brown, or skin-colored patches
• A hard, wart-like, or gritty surface texture that feels like sandpaper
• Lesions that may itch, burn, or feel tender to the touch
• Spots that come and go, sometimes disappearing temporarily and returning in the same location

Where Do Actinic Keratoses Appear? 

Actinic keratoses tend to develop on areas of skin that have received the most chronic sun exposure over a lifetime, such as the face, scalp (particularly in individuals with thinning hair or baldness), ears, neck, forearms, and the backs of the hands.

• Actinic keratosis on the face often appears on the forehead, cheeks, and nose, areas that receive direct sun exposure year-round. 
• Actinic keratosis on the nose can be persistent because the skin is thinner and harder to protect consistently. 
• Actinic keratosis on the scalp is common in men experiencing hair loss.

Mild, early-stage actinic keratosis may be easier to feel than to see. Patients may notice a rough or gritty spot before any clear discoloration appears. Actinic keratoses also tend to appear in clusters rather than as a single isolated lesion, reflecting the widespread nature of underlying sun damage. Any persistent rough or scaly patch on sun-exposed skin should be evaluated by a dermatologist, especially if it does not resolve on its own within a few weeks.

Is Actinic Keratosis Cancer?

Actinic keratosis is not cancer, but it is classified as a precancerous lesion. AKs develop from the same ultraviolet damage that causes skin cancer, and they share many of the same cellular changes seen in early squamous cell carcinoma. In effect, an actinic keratosis represents abnormal, sun-damaged cells that have not yet become fully cancerous but have taken the first step along that pathway.

About 5% to 10% of untreated actinic keratoses may become cancerous. Because it is not possible to predict which individual lesions will progress, and because the transition from AK to SCC can be subtle and difficult to detect visually, we recommend treating actinic keratoses early rather than adopting a wait-and-see approach.

Types of Actinic Keratosis

Common (Classic) Actinic Keratosis

The most typical presentation is a flat or slightly raised, rough, scaly patch that feels gritty to the touch. These lesions are usually pink, red, or skin-colored and tend to respond well to standard treatments like cryotherapy or topical therapy.

Hypertrophic Actinic Keratosis

Hypertrophic actinic keratosis is a thicker, more raised, and more prominent form of AK. These can develop a thick crust or even resemble a cutaneous horn. Because hypertrophic AKs can be difficult to distinguish from squamous cell carcinoma based on appearance alone, a biopsy is performed to make a diagnosis.

Lichenoid Actinic Keratosis

Lichenoid actinic keratosis is characterized by inflammation in and around the lesion. These AKs may appear red, slightly swollen, or irritated, and the surrounding skin often shows signs of active immune response. The inflammation reflects the body’s immune system reacting to the abnormal cells within the lesion.

Actinic Cheilitis

Actinic cheilitis is an actinic keratosis that affects the lip, most commonly the lower lip, which receives more direct sun exposure. It usually appears as persistent dryness, scaling, blurring of the lip border, or cracking that does not heal with standard lip care. Actinic cheilitis is considered a higher risk and should be evaluated and treated as soon as possible. 

Actinic Keratosis Causes and Risk Factors

Causes

The primary cause of actinic keratosis is cumulative UV radiation from sunlight over the course of a lifetime. UV exposure from tanning beds and other artificial sources contributes to the same type of damage. Over time, UV radiation damages the DNA within skin cells, leading to abnormal cell growth in the outer layer of the skin (the epidermis). This accumulated damage is what eventually manifests as an actinic keratosis.

Risk Factors

Certain individuals are more likely to develop actinic keratosis than others. Risk factors include:

• Chronic sun exposure, particularly without consistent sun protection
• Fair skin, light-colored hair, and light-colored eyes
• Age 40 and older
• A history of frequent or severe sunburns, especially earlier in life
• Living in sunny climates such as Florida or at high altitudes
• A weakened immune system, including organ transplant recipients and patients taking immunosuppressive medications
• Outdoor occupations or hobbies that involve prolonged sun exposure, such as construction work, landscaping, fishing, or golf

Reducing Your Risk

Prevention is always preferable to treatment. We suggest using a broad-spectrum SPF 30 or higher sunscreen every day (including on cloudy days), seeking shade during peak UV hours, wearing wide-brimmed hats and protective clothing, and avoiding tanning beds. Annual skin exams are also very important, particularly for patients with one or more risk factors.

Because of Florida’s year-round sun and high UV index, residents face an elevated lifetime risk of sun-induced skin conditions. Suncoast Skin Solutions is committed to preventive dermatology and partners with patients across Florida to monitor, manage, and minimize the impact of chronic sun exposure.

How Is Actinic Keratosis Diagnosed?

In most cases, a dermatologist can diagnose actinic keratosis through a thorough visual and tactile examination. Experienced providers are often able to identify AK on sight based on the characteristic texture, location, and appearance of the lesions. A dermatoscope, a specialized magnifying instrument, may be used to evaluate suspicious lesions more closely and distinguish AK from other skin conditions.

Accurate diagnosis matters because several other skin conditions can resemble actinic keratosis:

• Actinic keratosis vs. seborrheic keratosis: Seborrheic keratoses are benign, non-cancerous growths that are not caused by sun damage. They often appear “stuck on” the skin and, unlike AKs, do not carry any risk of becoming cancerous. Seborrheic keratoses tend to be darker, waxier, and more sharply defined than AKs.
• Actinic keratosis vs. basal cell carcinoma: Basal cell carcinoma (BCC) is already a form of skin cancer, whereas actinic keratosis is precancerous. BCCs often appear as pearly bumps, sometimes with visible blood vessels, and may bleed or ulcerate.
• Actinic keratosis vs. squamous cell carcinoma: SCC is the invasive cancer that untreated AKs can eventually progress into. SCCs tend to be thicker, firmer, and more tender and may grow rapidly compared to a typical AK.

Because these conditions can be difficult to tell apart without clinical training, patients should avoid self-diagnosis and instead have any persistent or changing lesion evaluated by a qualified dermatologist.

How to Treat Actinic Keratosis

There are several treatments available for actinic keratosis. The most appropriate treatment depends on the number, size, thickness, and location of the lesions, as well as the patient’s overall skin health. Our board-certified dermatologists tailor treatment plans to each patient’s individual needs.

Cryotherapy (Liquid Nitrogen)

Cryotherapy is the most common treatment for individual actinic keratoses. During the procedure, liquid nitrogen is applied directly to the lesion to freeze and destroy the abnormal cells. Actinic keratosis cryotherapy is quick, performed in the office, and highly effective for isolated or small numbers of lesions. Treated areas typically blister, scab, and heal over one to two weeks.

Topical Treatments

Prescription creams and gels applied at home are an effective option when multiple actinic keratoses are present over a broader area (an approach sometimes called field therapy). Common actinic keratosis creams include fluorouracil (5-FU), imiquimod, ingenol mebutate, and diclofenac. These treatments are applied over several weeks and work by targeting abnormal cells across the treated area, including subclinical lesions that are not yet visible to the eye.

Photodynamic Therapy (PDT)

Photodynamic therapy is useful for widespread actinic keratoses and field cancerization. A light-sensitizing agent is applied to the affected skin and then activated by a specific wavelength of light, which selectively destroys abnormal cells while sparing surrounding healthy tissue. 

Chemical Peels

Medium-depth chemical peels can treat superficial actinic keratoses across a broad area, particularly on the face. 

Curettage

For thicker or more resistant lesions, curettage involves scraping the actinic keratosis from the skin surface, often followed by electrodessication to destroy any remaining abnormal cells. This actinic keratosis removal approach is used most commonly for hypertrophic AKs or lesions that have not responded to other treatments.