What is the effect of excessive UV exposure on the immune system?

Excessive UV exposure has a well-documented effect of decreasing the immune response. This happens because UV radiation can lead to a reduction in the number and function of certain immune cells, particularly those involved in the skin's immune response, such as Langerhans cells. When the immune response is diminished, the body's ability to detect and respond to pathogens, such as viruses and bacteria, is compromised, increasing the risk of infections and potentially allowing for the development of skin cancers.

In addition, chronic UV exposure can lead to immunosuppression, which is a state where the body is less capable of mounting an effective immune response. This is particularly concerning for individuals who are frequently exposed to UV radiation, such as those who tan regularly. Essentially, while moderate sun exposure can be beneficial for vitamin D production and other health aspects, excessive exposure undermines the immune system, making it essential to practice safe sun exposure habits.