Eczema Treatment: UV Phototherapy
UV Phototherapy comes in two forms: Non-Targeted and Targeted.
Ultraviolet (UV) light is a natural part of all sunlight.
UVA light (320 to 400nm) and UVB light (280 to 320nm) are the UV radiation wavelengths which reach the surface of the earth. It is generally known that exposure to too much sunlight, specifically too much UVA and UVB light, causes sunburn, aging of the skin, and in some cases, skin cancer. Sunblock is generally used to keep UVA and UVB light from reaching the skin it's applied to.
It is less generally known that sunlight strongly affects the immune system of the skin in beneficial ways for patients with psoriasis, eczema, vitiligo, and various other skin conditions. One common characteristic of over-exposure to the UV radiation of the sun (sunburn) is a reddening of the skin called “erythema”, caused by an increase in capillary blood supply called “hyperiemia”.
UV light interrupts the cycle of immune system activity which perpetuates eczema, acting as a natural immunomodulator.
UVA and UVB light act in many ways to modulate the activity of the immune system in the skin. UVB light has enough energy to induce "apoptosis", or cell death, in abnormally proliferating skin cells.The application of UVA and UVB light as a safe and effective treatment for eczema has a long and well studied history, and are continued to be researched. UV phototherapy can be less toxic than other treatments, and often times is combined with glucocorticoids and other medications.
Topical and systemic drugs have been utilized in conjunction with UV phototherapy to:
- Improve therapeutic benefit, with the two treatments working better together than either alone
- To achieve the same therapeutic benefit as the drug alone, while being able to reduce the drug dosage which reduces associated toxicity, side effects, and potential tachyphylaxis (eventual non-effectiveness of drug)
There are several types of UV phototherapy devices, with treatments issued either by non-targeted or targeted devices. Non-targeted refers to delivering lower dosage UV light to healthy and eczema skin alike, two to several times per week. Targeted phototherapy refers to delivering higher dosages of UV light to only eczematous skin, sparing healthy skin, two to several times per week.