Lasers too are beginning to find a role in the treatment of acne. They work by emitting minimally divergent, coherent light that can be focused over a small area of tissue. Pulsed
dye laser (585 nm) can be used at lower fluences to treat acne. Instead of ablating blood vessels and causing purpura, the lower fluence can stimulate procollagen production by heating dermal perivascular tissue (121). The beneficial effects of a single treatment can last 12 weeks (125). The 1450 nm diode laser has also demonstrated significant efficacy in treating acne (126,127). This laser works by causing thermal damage to the sebaceous glands. The concurrent use of a cryogen spray device protects the epidermis (128).