Why ultra violet light may help

People with psoriasis may benefit from UVB light, one of the forms of Ultra Violet light that comes from the sun. There are three forms: UVA, UVB and UVC. Short wavelength UVC is absorbed by the ozone layer and does not reach the earths surface at all. The UV light which does reach us is mainly long wave UVA, with some intermediate wavelength UVB, and it is the UVB rays which may help psoriasis. UV light helps to power chemical reactions that affect the function of the cells. In psoriasis, this means that the cells do not multiply so rapidly and behave more like normal skin. Too much UVB however is not a good thing because it burns. Even UVA is not harmless and too much of both can prematurely age the skin and increase the risk of skin cancer. You really do need to take care even if you do find that sunshine helps your skin. You are at highest risk if you are fair or red haired and your skin does not tan easily. Because ultra violet light is so effective for so many people with psoriasis doctors use it in various artificial forms. The British Photodermatology Group is an advisory group on the use of UV light in the UK.

What is UVB treatment?

UVB contains a wide range of wavelengths and is used to treat guttate psoriasis or plaque psoriasis, which is resistant to topical treatments (i.e creams and ointments). In the past few years a more defined form of UVB has been developed, known as 'narrow band', and this is proving effective. The aim is to clear the skin and this can take up to 30 treatments over a period of weeks. This treatment is administered in hospital under controlled conditions using trained staff.

What is PUVA?

This is a light treatment using a psoralen and UVA treatment. UVA on its own is not active in skin disease but if given with a psoralen, which makes the skin more sensitive to light, it can be very effective. Psoralen is derived from plants and is normally taken as a tablet or sometimes in a bath. There are three groups of people who will be considered for PUVA treatment:-
people with severe psoriasis that is not responding to topical treatments,
people whose psoriasis returns within three to six months of successful treatment as in -patients or day patients,
people who do not want topical treatment and for whom UVB has failed.
Like UVB treatment this is administered in hospital under controlled conditions using trained staff.

Side effects

The most common short-term side effects of PUVA are nausea, itching and redness of the skin. The National Psoriasis Foundation suggest that drinking milk or ginger ale, taking ginger supplements or eating while taking oral psoralen may prevent nausea. Antihistamines, baths with oatmeal products or applying topical creams/ointments/gels containing capsaicin (an extract of hot peppers) may help relieve the itching caused by PUVA.

Are there any risks?

UV radiation causes skin damage and, eventually, skin cancer, and treatments therefore have to be rationed. Doctors will not put patients at unnecessary risk. Care should be taken with the number of treatments over one year and indeed over a lifetime. This will vary from person to person depending on skin type and total dose administered. It is most important to be guided by your doctor.

Sunbeds and Sunlamps

Many dermatologists would advise against using a sunbed as UV light can lead to the development of skin cancers. UV treatment in hospital is very carefully controlled and using a sunbed outside the hospital setting makes it difficult to ensure correct dosage or that you are receiving the right kind of UV light. It is also true that many pure UVA sunbeds are ineffective for the treatment of psoriasis.

Safe in the sun

Whether sunlight, real or artificial, will help you may depend on a number of factors such as the type of psoriasis, your age, your skin type, previous treatment etc. Talk to your doctor or nurse about whether you should try sunlight. Please do not allow embarrassment about your skin prevent you from spending time in the sun if you feel it would be beneficial.

If you do go out in the sun follow these general guidelines:

Avoid being out in the hot sun between 11 a.m. and 2 p.m. However remember that the time of day is not always the best indicator of the sun's strength (owing to differences in longitude and latitude in different parts of the world) it may be better to check the power of the sun by the shadow it throws. If your shadow is shorter than you are the sun is more likely to be burning.

Shade does not always give you protection. Water, sand and concrete can all reflect sunlight and increase your chances of burning. Sunlight can also penetrate glass, cloud, water and fine hosiery such as tights.

Use the sunscreen, which suits your skin, but do not just apply it once and forget about it. Re-apply every few hours or more often if you go swimming and especially if you towel yourself dry afterwards.

Loose fitting clothing is better protection against the sun than tight clothing and dark colours are more protective than light colours.

Keep your skin well moisturised.

Remember that it is important not to burn as this can increase your risk of skin cancer.

This is a brief description of Ultra Violet Light; there is ongoing research into the subject - for additional information contact the Psoriasis Association.