What is the primary causative factor in the development of actinic keratosis?

Actinic keratosis is primarily caused by prolonged exposure to ultraviolet (UV) radiation from the sun. This condition is characterized by rough, scaly patches on sun-exposed skin, particularly in areas such as the face, ears, scalp, and backs of the hands. The harmful effects of UV rays lead to DNA damage in skin cells, which disrupts the normal process of skin cell turnover and can result in pre-cancerous lesions like actinic keratosis.

While genetics, viral infections, and environmental irritants can play roles in skin health and the development of other dermatological conditions, they are not the primary factors in actinic keratosis. The connection between sun exposure and the development of actinic keratosis is well-established; it is considered a direct consequence of cumulative UV damage. Factors such as fair skin types, age, and immunosuppression can also increase susceptibility, but the primary causative factor remains chronic sun exposure, reinforcing the need for sun protection measures to prevent this condition.