Actinic Keratosis

Actinic keratosis (AK) is a common skin condition caused by long-term sun exposure, particularly ultraviolet (UV) radiation. It is also known as solar keratosis or senile keratosis.

Causes and Risk Factors

Actinic keratosis is primarily caused by cumulative UV radiation from the sun or tanning beds. The risk of developing AK increases with:

• Prolonged sun exposure, especially during childhood and adolescence
• Fair skin, blonde or red hair, and light eye color
• Age, as most cases occur in people over 50 years old
• Weakened immune system, such as in organ transplant recipients
• History of previous skin cancers or precancerous lesions

Symptoms and Signs

Actinic keratosis typically appears as small, rough, scaly patches on sun-exposed areas, such as:

• Face, especially the nose, cheeks, and forehead
• Ears
• Neck
• Hands, particularly the backs of the hands
• Bald scalp

These lesions can be:

• Pink, red, or flesh-colored
• Rough to the touch, like sandpaper
• Flat or slightly raised
• Singular or multiple, ranging in size from a pinhead to several centimeters in diameter

Diagnosis and Treatment

A diagnosis of actinic keratosis is typically made through:

• Visual examination by a healthcare professional
• Dermatoscopy, a non-invasive technique using a specialized microscope
• Biomicroscopy, which uses a combination of dermatoscopy and other imaging techniques
• Skin biopsy, in some cases, to rule out skin cancer

Treatment options for actinic keratosis include:

• Cryotherapy, using liquid nitrogen to freeze the lesion
• Topical creams or gels, such as fluorouracil (5-FU), imiquimod, or diclofenac
• Photodynamic therapy (PDT), which uses a light-sensitive medication and a specific wavelength of light to destroy the lesion
• Surgical excision, in some cases, for larger or more suspicious lesions

Prevention and Prognosis

To prevent actinic keratosis, it is essential to:

• Use sunscreen with a Sun Protection Factor (SPF) of at least 30 daily
• Wear protective clothing, such as wide-brimmed hats and long-sleeved shirts
• Seek shade, especially during peak sun hours (10am-4pm)
• Avoid tanning beds and artificial UV radiation sources

If left untreated, actinic keratosis can progress to squamous cell carcinoma, a type of skin cancer. However, with proper treatment and prevention measures, the prognosis is generally good.