The primary cause of actinic keratosis is ultraviolet (UV) radiation, which may be from sunlight or other sources, such as tanning beds. There are, however, several other potential causes of the skin condition, such as X-ray, industrial chemicals and some medications. Each of these causes and risk factors is discussed in more detail below.
The ultraviolet radiation from sunlight is the cause of the overwhelming majority of cases of actinic keratosis. The damage to the skin caused by the UV rays is cumulative - the more time that an individual spends in the sun, the more likely they are to be affected.
As a result of this cumulative effect, it is important for individuals to protect themselves from excessive exposure to sunlight on a daily basis, particularly if they are frequently outside.
Approximately 70-80% of UV radiation from sunlight can pass through clouds and, as a result, one is not exempt from potential skin damage even on cloudy days.
Similar to sunlight, the light from the lamps in tanning salons also emit ultraviolet radiation and can cause actinic keratosis. In fact, the concentration of the harmful UV rays can often be higher and is directed towards the skin from short distances, increasing the potential for harm.
Exposure to X-rays has also been linked to the development of actinic keratosis and may be associated with causing the condition. For this reason, in addition to other potentially harmful effects of X-rays, it is prudent to minimize exposure to X-radiation wherever possible.
Frequent exposure to some industrial chemicals may also have the potential to cause actinic keratosis. For example, people who work with polycyclic aromatic hydrocarbon (PAH) containing substances (e.g. coal or tar) are more likely to develop actinic keratosis. This suggests that the chemical may have a causative role to play in actinic keratosis.
People with a compromised immune system due to certain medications are also more likely to be affected by actinic keratosis. This is because their body is less equipped to protect itself from the harm of UV radiation.
Patients who have a medical history of chemotherapy, AIDS medications and immunosuppressive medications to support organ transplantation are among those most likely to be affected.
Risk Factors for Actinic Keratosis
Although exposure to UV radiation and other potential causes play a big role in the development of actinic keratosis, these are not the only factors. Some people are predisposed to the skin condition due to their genotype or other factors. They may be more likely to get actinic keratosis if they:
- Have fair skin with freckles
- Have blond or red hair
- Have blue, green or hazel eyes
- Live near the equator
- Work in an outdoor occupation
Elderly people are most likely to be affected by actinic keratosis due to the cumulative effect of UV radiation on the skin cells. However, even young adults may be affected in some cases, particularly if they spend a significant amount of time in the sun.
Reviewed by Afsaneh Khetrapal BSc (Hons)