What environmental factor is a significant cause of actinic keratosis?

• A. Cold temperatures
• B. High humidity
• C. Long-term sun exposure
• D. Indoor lighting

Answer: (C)

Actinic keratosis is primarily caused by prolonged exposure to ultraviolet (UV) radiation from the sun. This skin condition occurs when skin cells undergo changes due to the damage inflicted by UV rays, leading to rough, scaly patches on sun-exposed areas of the skin. The risk significantly increases with factors such as time spent outdoors without adequate protection, especially in individuals with fair skin who are more susceptible to UV damage.

Cold temperatures, high humidity, and indoor lighting do not contribute to the same degree of skin cell damage associated with UV exposure. While these factors may influence overall skin health or comfort, they are not recognized as significant risk factors for developing actinic keratosis. Thus, long-term sun exposure stands out as the primary environmental factor linked to the onset of this condition.