Blue light therapy is sometimes promoted as an effective treatment for acne, although people who undergo standard therapy sessions are typically not completely cured of acne. Clinical studies have shown that this method clears about 55% of pimples, so it's not a cure, but a treatment that may help reduce some acne. The light also can kill some of the acne causing bacteria, P. vulgaris. Blue light treatment is still being monitored for overall safety and effectiveness. So far, few complications from this therapy have been reported, but long-term effects are not yet known.
There are several apparent benefits to blue light therapy. It's painless, with relatively short therapy sessions, and the light does not contain UV rays, so it's not considered to be potentially cancer causing. Patients generally have two, 15-minute sessions every week for four weeks. People have also found that inflammatory acne may respond well to the treatment.
One type of acne that does not respond well to this therapy, and which may actually worsen as a result of treatment, is called nodulocystic acne. This form of acne usually shows on the skin as numerous bumps that are generally painful to the touch and may be red or purple in color. Cysts resembling boils may also be present and may be filled with pus. This form of acne may get worse with blue light treatment, so people with acne should be properly diagnosed before undergoing this therapy.
There are a few mild side effects to blue light therapy. Some pigment changes to the skin can occur, although they usually are temporary. Treated areas treated may also experience slight inflammation and may become especially dry.
It’s unclear exactly how long blue light treatments will help the skin remain clear, and it bears repeating that this is not a cure for acne. Some people experience significant improvement while others see minor, transient clearing. Generally, effective treatment in the best of circumstances results in a 50% reduction in acne. As a result, combined therapies are being experimented with.
One method under investigation is using the topical 5-aminolevulinic acid (ALA) before blue light treatments. ALA makes the skin less resistant to light, and may make it more effective in killing acne causing bacteria. It does have more side effects than blue light alone and may cause hair follicles to swell. People who are treated with ALA are instructed to use sunscreen for 48 hours after each treatment to avoid serious sunburn. Like many acne treatments now available, ALA with blue light therapy is considered potentially effective. Currently, there is no standard “cure” for acne.