(October 20, 2008 - Insidermedicine) Laser therapy combined with light-sensitive medication produces molecular changes in the skin that explain why this treatment improves the skin's appearance, according to research in the the Archives of Dermatology.

Here are some facts about photodynamic therapy:

. Medication that is sensitive to light is placed on the skin and treated with a special type of laser light.

. Photodynamic therapy improves the appearance of sun damaged skin, producing changes that are visible to the eye and at a microscopic level.

. It is unclear what, if any, changes photodynamic therapy produces at a molecular level.

Researchers from the University of Michigan Medical School treated the forearms of 25 adults aged 54 to 83 with a solution containing 5-aminolevulinic acid followed by pulsed-dye laser. Prior to treatment, all the patients had sun damaged skin on their forearms.

After 6 months, repeated testing of samples of the treated skin revealed that the outer layer thickened by over 40%. In addition, levels of proteins, enzymes, and other substances associated with the growth and development of new skin cells and with collagen production had increased.

Today's research provides evidence at the molecular level for the benefits of photodynamic therapy, which can improve the appearance of sun damaged skin.

For Insidermedicine in Depth, I'm Dr. Susan Sharma.