The Truth About Sunscreens

Sunscreens first came into use in the 1940s and the concept of the sun protection factor (SPF) was developed in the 1960s. The purpose of these agents is to protect against ultraviolet light. Ultraviolet light has been divided into three bands: ultraviolet C, which never reaches the surface of the earth, ultraviolet B which extends from 290-320 nanometers, is the primary cause of sunburn and does not penetrate window glass and ultraviolet A 320-400 nanometers, which does penetrate window glass and is adjacent to the visible light spectrum.

At the time of development of the SPF rating system and the development of the first of the modern sunscreens, it was believed that ultraviolet B was the bad actor and a good sunscreen had only to provide good Ultraviolet B protection. This was the initial focus of sunscreen development.
One of the significant advances in dermatologic therapy was the use of ultraviolet A therapy to treat a variety of skin conditions, including psoriasis. As a result of these treatments, it became clear that considerable damage to the skin was occurring. There was more wrinkling and increased freckling and brown skin discoloration. The skin surface became more rough and mottled. It was also clear that too much ultraviolet A can cause a burn which is different from an ultraviolet B burn in that it begins about 24 hours after exposure.
Patients treated with Ultraviolet A therapy showed an increased incidence of squamous cell carcinoma and an eventual increased incidence of melanoma.
As a result of these findings it has become clear that it's important to choose a sunscreen that has both good ultraviolet A and ultraviolet B protection. How to do this will be covered in the next post.

Gerald N. Bock MD
California Skin & Laser Center
Stockton & Lodi, CA

Comments

[laser hair removal montclair]

Its very informative blog i think it could be a good subject to explore.

sphin

[ontario dermatologists]

Its very informative to know more about sunscreens,Keep posting!

sphin

[Palm Springs Cosmetic Surgeon]

You can never overlook the importance of using a good sunscreen when being exposed to sunlight for an extended period of time. This is especially important for children. The sun's UV rays can be very harmful.