Many people with psoriasis notice an improvement in their skin after they have been in the sunshine. The use of the sun’s rays has been used to treat psoriasis for over a century, however, of the many different ultraviolet rays emitted by the sun, only UVA and UVB are helpful to people with psoriasis. Ultraviolet light reduces inflammation in the skin, which is why it can be effective for psoriasis and other inflammatory skin conditions.
There are two different types of ‘UV’ therapy that are used to treat psoriasis. Narrowband UVB (also known as ‘TL-01’, after the type of bulb used) uses the UVB part of the spectrum, and is often used to treat guttate or plaque psoriasis. The other type of ‘UV’ therapy is known as PUVA, and is a combination of the UVA part of the spectrum and a chemical called psoralen (this is where the ‘p’ in PUVA comes from). UVA light is not useful in treating psoriasis on its own, and so psoralen is needed to make the skin more sensitive to it. PUVA might be used if UVB therapy has not worked, and can be particularly effective for psoriasis on the hands and feet, due to being better at penetrating thicker plaques of psoriasis.
Remember - using a sunbed at a gym, salon or spa is not the same has having UV therapy in a hospital setting. Hospital-based UV treatment uses only the specific part of the spectrum that is useful to treat skin conditions. This is not the case on a sunbed, where a much broader spectrum is used. Many sunbeds use mostly, or entirely, UVA light, which is ineffective for treating psoriasis without the added psoralen. Therefore, using sunbeds means taking on the risks of UV exposure, without much of the benefit to psoriasis.
UV treatment in hospital is very carefully controlled – a Dermatologist will tailor the right amount of UV for each individual, and monitor the results. If a person uses sunbeds or an at-home lamp in addition to this, it makes it difficult to ensure they are receiving the correct dose for them.
Click here for more information on the different types of UV therapy, regimes, side effects and risks.