P. acnes naturally produces porphyrins, substances that strongly absorb light. The role of light devices is to activate porphyrins and ultimately produce singlet oxygen which will result in bacterial death but also destroy sebaceous glands .
Photodynamic therapy has been available for around 15 years. Its effectiveness has been well demonstrated, the main disadvantage has been its side effects which include pain, erythema an hyperpigmentation. In the past years, several protocols have been adjusted to provide better tolerance and more effectiveness.
New devices using narrow band ultraviolet light (NB-UVB) has proved to inhibit P acnes with a relatively low dose. We have also previously known that NB-UVB modulates the body defense response mediated by cells creating a synergistic effect.
We expect promissory results from short courses of NB-UVB therapy in combination with other local treatments available depending on the severity of acne lesions.