Light Therapy for Skin Disease

Understanding Phototherapy
Phototherapy is the use of selected wavelengths of light to treat disease. In its most modern version, Narrowband UVB, it is an effective, safe, and patient preferred therapy, whether delivered in a physician's office or in the patient's home. Starting with the 1903 Nobel Prize winning work of Niels Finsen, phototherapy has evolved to precisely target the most therapeutically useful wavelengths and to avoid unnecessary exposure to unproductive portions of the electromagnetic spectrum.

Common Treated Diseases
The most commonly treated photoresponsive diseases are psoriasis, vitiligo and eczema. In psoriasis, a patient will require a course of 20-30 treatments over the course of about a month to clear their skin. Typically, the patient's skin will then remain clear for a period of months before needing another course of therapy.

Treatment Regimen
The treatment regimen consists of gradually increased doses of ultraviolet delivered to the patient' skin. The doses are measured in milliJoules per square centimeter (mJ/cm^2) and will typically take less than 5 minutes. Depending on the type of device used, the dose increases will be handled automatically, requiring minimal staff training. Operating modern phototherapy equipment is both simple and well reimbursed by insurance, causing little disruption to an existing practice.

Patient Response
Interestingly, a recent survey conducted using the National Psoriasis Foundation's email database showed that patient treatment preference is higher for phototherapy than for any other psoriasis treatment, with 62% of patients preferring in-home phototherapy, followed by 30% preferring in-office phototherapy. This is much higher than the patient preference for pharmaceutical intervention in psoriasis. This preference for phototherapy makes sense in light of its effectiveness (up to 82% of psoriasis patients are cleared) and its mild side effect profile (most prominently short term erythema).

Making Phototherapy Easily Accessible
Recent innovations in many areas of healthcare, from renal dialysis to blood glucose testing, have evolved from therapies once conducted only as inpatient services in large institutions to therapies practiced in increasingly smaller clinics, and then eventually in the patient's home. The same is true of phototherapy. It was at first available only as a complex inpatient regime requiring weeks of messy coal tar applications. It can now be done safely and effectively in a patient's home. A series of studies, including the large PLUTO study from the Netherlands shows that home phototherapy is equal to clinical phototherapy in terms of both clinical outcome and the occurrence of side effects.

Home Phototherapy
Home phototherapy devices are essentially scaled down versions of clinical equipment, using exactly the same wavelengths of light. They range in size from small devices for treating small spots to full-body machines. Most manufacturers of these devices include treatment limiting features which allow a prescriber to retain control of the treatment process by requiring follow-up office visits to obtain electronic refills.

1Takeshita, et al. Patient Reported Priorities for Comparative Effectiveness Research in Psoriasis Poster presented at Pso Paris 2013.

2Walters, et al. Suberythemogenic narrow-band UVB is markedly more effective than conventional UVB in treatment of psoriasis vulgaris,. Journal of the American Academy of Dermatology, Vol 40, Issue 6, June 1999, Pages 893-900

3Koek, et al. Cost effectiveness of home ultraviolet B phototherapy for psoriasis: economic evaluation of a randomised controlled trial (PLUTO study) BMJ 2010;340:c1490