Overview

Actinic keratosis (AK), also known as solar keratosis, is a rough, scaly patch on the skin that develops due to prolonged exposure to ultraviolet (UV) radiation from the sun or tanning beds. It is considered a precancerous condition because, if left untreated, it can potentially progress to squamous cell carcinoma, a common form of skin cancer. Actinic keratoses are most commonly found on sun-exposed areas such as the face, ears, neck, scalp, forearms, and hands, and are more prevalent in older adults with fair skin.

Causes

The primary cause of actinic keratosis is cumulative sun exposure over time. Specific contributing factors include:

• Prolonged sun exposure: Repeated exposure to ultraviolet (UV) rays from the sun damages skin cells, leading to abnormal cell growth.
• Use of tanning beds: Artificial UV radiation also increases the risk of AK.
• Fair skin: Individuals with light skin, blond or red hair, and light eyes are more susceptible due to lower melanin protection.
• Age: Most cases occur in people over the age of 40, after years of sun damage.
• Weakened immune system: People with compromised immunity, such as organ transplant recipients, are at greater risk.
• Geographic location: Living in sunny climates or at high altitudes increases UV exposure and risk.

Symptoms

Actinic keratosis presents with several recognizable signs, particularly in areas frequently exposed to the sun:

• Rough, scaly patches: The hallmark symptom is a dry, crusty, or scaly patch of skin that feels like sandpaper.
• Color changes: Lesions may appear red, pink, brown, or flesh-colored.
• Small size: They typically range from a few millimeters to 2 centimeters in diameter.
• Flat or slightly raised: Patches can be flat or slightly elevated with a rough texture.
• Multiple lesions: Often, multiple actinic keratoses develop in the same area, known as a “field” of damaged skin.
• Occasional tenderness or itching: Some spots may cause mild discomfort or a burning sensation.

Diagnosis

Diagnosis of actinic keratosis is typically based on a clinical evaluation:

• Physical examination: A dermatologist examines the skin’s texture and appearance.
• Touch test: AK lesions often feel rough before they are visibly noticeable.
• Dermatoscopy: A handheld device may be used to examine the lesions more closely.
• Skin biopsy: If the lesion appears suspicious for skin cancer, a small sample may be taken for laboratory analysis to rule out squamous cell carcinoma.

Treatment

Early treatment of actinic keratosis is important to prevent progression to skin cancer. Common treatment options include:

• Topical medications: Prescription creams or gels, such as 5-fluorouracil (5-FU), imiquimod, or diclofenac, are used to destroy abnormal cells.
• Cryotherapy: Freezing the lesion with liquid nitrogen is a common and quick in-office treatment.
• Photodynamic therapy (PDT): A photosensitizing agent is applied to the skin, followed by light exposure to destroy abnormal cells.
• Curettage and electrosurgery: Scraping off the lesion followed by electrosurgical treatment to remove residual cells.
• Laser therapy: Ablative lasers can be used to remove damaged skin cells.
• Field treatment: For areas with multiple lesions, field-directed therapies like topical treatments or PDT are used to treat all affected skin.

Prognosis

The prognosis for actinic keratosis is generally good with early detection and treatment:

• Excellent outcome with treatment: Most actinic keratoses can be completely cleared with appropriate treatment.
• Risk of recurrence: New lesions can develop in previously sun-damaged skin, so ongoing monitoring is important.
• Potential for progression: A small percentage of untreated actinic keratoses may progress to squamous cell carcinoma.
• Preventable with sun protection: Regular use of sunscreen, protective clothing, and avoidance of tanning beds can reduce the risk of new lesions.
• Importance of follow-up: Regular dermatologic check-ups help catch new lesions early and manage them promptly.

With proactive care, most individuals with actinic keratosis can prevent serious complications and maintain healthy skin.