Lights For Acne

I had a friend ask me about light treatments for acne, so I thought I should review that today. First of all, light therapy is not for most people with acne. For the most part it is not effective enough for many people seeking help with their acne. The cost-effectiveness of light therapies in acne have not been well studied, but in my opinion you get a lot more bang for your buck with other acne treatments. That being said, there are a select group of patients for whom light therapy for their acne is the right choice. These include people who get easily irritated by topical treatments.

Light therapies have not been compared well to conventional treatments (eg, pills and creams).

There are several types of light used in acne including visible light (especially blue lights), various lasers, a type of light called Intense Pulsed Light (called IPL by dermatologists), and a type of light treatment called Photodynamic Therapy (what we call PDT).

Very few trials of light in acne are well designed. Many of these products are what the FDA calls "cleared" for acne, and this should not be confused with FDA "approval." The standard for getting a device "cleared" is very low and does not mean that the device actually works. With that in mind I will talk about the various types of lights.

Blue light - This is a popular type of treatment for acne. Blue light comes in a variety of wavelengths and intensities. Some blue lights give intense pulses of light at narrow wavelengths (415-425 nanometers), while others use longer wavelengths (470 nanometers). The theory behind blue light comes from the study of Propionibacterium acnes, which makes a substance that you can excite at 415 nm to kill it. In several short-term studies it performs about as well as using 5% benzoyl peroxide. Some light sources are inexpensive and available for home use. Some units, which may or may not emit stronger light than the home units are available only at the dermatologist's office. It has NEVER been shown to work for anything more than moderate acne.

Intense pulsed light - Unlike laser, which is made up of one wavelength of light, intense pulsed light (IPL) typically consists of a range of wavelengths (e.g., 400-1200 nanometers or 530-710 nanometers). It can be used alone for acne or in combination with topical chemicals to make skin more reactive to the light. It is probably effective for mild to moderate acne, but you need to get the light in the office, and it costs somewhere in the neighborhood of hundreds of dollars per treatment. There are not great studies looking at IPL alone without the use of photosensitizers.

Photodynamic therapy - More commonly used for treating a type of precancer (actinic keratosis), this type of therapy can be used with IPL or with a blue or red light. This type of treatment requires the application of a chemical, most often aminolevulinic acid (ALA), prior to exposure to a light. Like with the other types of light treatment, the studies are limited by small numbers and mediocre design. It probably works better than IPL or visible light alone, but the side effects can include photosensitivity, blistering, crusting, and burning, which are rare with IPL or visible light alone.

So, my take on light therapy is that there is definitely a role for it, but dermatologists haven't worked out exactly what that role is. For people who really hate putting on creams or taking pills it may be the way to go. You probably get more efficacy from PDT--treatment with light in combination with a photosensitizer-- than from light exposure alone. The skin cancer risk of exposure to these lights has not been worked out.