Like Dr. Oppenheim, we do not advocate IPL treatments for acne scars. Bleaching creams and chemical peels are an excellent solution and we would also add q-switched and pulsed dye lasers to the mix.
The reason that IPL is ineffective is that it is not specific enough in the type of light it uses. Q-switched lasers we use for brown acne scars have a 1064 nm wavelength which is ideal for removing the brown color. The 585 nm pulsed dye lasers are ideal for vascular conditions such as red acne scars. IPL unfortunately does not have one wavelength of light but instead many. Therefore it is a jack of all trades and master of none.
Try the chemical peels and bleaching creams first for brown scars and move to the q-switched laser if they does not help. Try pulsed dye lasers first for red acne scars. Good luck.
Web reference: http://www.celibre.com/acne-scars.aspx