There are two main light-based modalities for treating acne: IPL using the so-called blue specturm, with or without Levulan and laser.
With PDT, photodynamic therapy, a liquid is applied with a special stick ( 8 -amino-levulinic acid, Levulan, with a "kerastick". The patient then waits for 30 minutes and is then placed in from of a Blu-light. Those who do not have a Blu-light might use the IPL device.
We have this device in our office and we do utilize it. While I think it is quite effective, and a useful weapon in our fight against acne, I would have to temper Dr. Persky's enthusiasm and say I have found it about as effective as a good antibiotic. In fact, that is one of its advantages: it helps fight acne without the use of an antibiotic. The cost is not by any means exorbitant, $180 with the kerastick and $80 without. Usually, two treatments are required.
PDT therapy works in an interesting manner. The bacteria that causes acne, P. acnes emits a chemical called porphyrins. The Levulan which is applied is attracted to the porphyrins and the porphyrins soak it up. Then the light uses the combination as a chromophore, a color to which it is attracted. The beam, attracted to the porphyrins-Levulan, then kills the nearby bacteria.
Lasers, notably the pulsed dye laser and nd YAG laser work in an entirely different, and much less sophisticated. It basically damages the sebaceous (oil) glands. The oil glands then produce less sebum and acne improves. For fencing afficionados, it is the difference between epee and sabre. Laser is quite a bit more expensive and runs about $300 a treatment.
