UVB light, which is present in sunlight, can reduce skin inflammation and slow the excessive growth of skin cells that cause psoriasis plaques. With UVB phototherapy, your skin is exposed to an artificial source of UVB light on a set schedule.
There are two types of UVB treatment: narrowband (NB-UVB) and broad band (BB-UVB). NB-UVB releases a smaller range of UV light and may clear psoriasis more quickly and with longer remission periods, notes the National Psoriasis Foundation (NPF). NB-UVB may also need fewer treatments per week to be effective.
According to joint guidelines from the NPF and the American Academy of Dermatology (AAD), NB-UVB is preferred over BB-UVB, given its greater efficacy, quicker treatment response, and lower rates of side effects.
UVB treatment can be administered in the following ways.
Localized Units UV light can be emitted via small units or lamps (for areas such as the hands and feet), full-body units, or handheld units.
Excimer Laser This laser emits a high-intensity, targeted UVB beam. It’s effective for mild to moderate psoriasis, and particularly for scalp psoriasis, according to the NPF.
Home Phototherapy Treatment After an initial treatment at a medical office or clinic, your doctor may prescribe a light unit you can use at home. You’ll follow your healthcare provider’s instructions and have checkups.
PUVA Therapy and Red Light Therapy
PUVA is phototherapy that combines exposure to UVA rays with a medicine called psoralen. UVA light is relatively ineffective for psoriasis if it isn’t used with psoralen, notes the AAD. Psoralen can be applied topically, mixed in water as a bath, or taken orally.
PUVA can be used to treat plaque psoriasis, guttate psoriasis, and psoriasis on the palms of hands and soles of feet.
Although many studies have shown that PUVA therapy can be more effective than NB-UVB, NB-UVB is the preferred treatment for plaque psoriasis because of superior safety, simplicity, and lower cost.
Red light therapy (RLT) is a kind of photomedicine, using light to treat skin conditions. When photons (particles of light) are placed near the skin, they enter tissues and activate chromophores (a part of a molecule that gives it its color), which triggers changes in cells. RLT shows promise in psoriasis treatment. Results from a handful of small studies suggest it can improve psoriasis symptoms, but more research is needed.
