How does photodynamic therapy work?

Photodynamic therapy requires three components: a photosensitizer; a light source; and oxygen.

Photosensitizers are topically applied solutions that cause certain types of abnormal cells to produce light-absorbing molecules called porphyrins. This change allows the light treatment to target the abnormal cells.

After applying a topical photosensitizer, a medical light source is focused on the skin to activate it. This light source may provide blue light, red light, or intense pulsed light (IPL). A doctor will decide what light source is best for the individual. Combined with the photosensitizer and the presence of oxygen, the light helps to destroy pre-cancer cells, acne cells and bacteria. PDT also reduces the size and activity of the oil-producing glands on the skin, known as the sebaceous glands.