Why ultraviolet light can be useful
Psoriasis sufferers may benefit from exposure to UVB light, one of the three wavebands of ultraviolet light that comes from the sun. Of the three wavebands - UVA, UVB and UVC – the shorter wavelengths in the UVC part of the spectrum are absorbed by the ozone layer and do not reach the earth's surface. The UV light which does reach us is mainly of the longer UVA wavelengths, with some intermediate UVB and it is the UVB rays which are most beneficial to those of us with psoriasis. UV light has many effects on skin and cell function. In psoriasis, at least one of the effects of UV light therapy is that cells do not multiply so rapidly and the anti-inflammatory effects are also import
However, too much exposure to UVB is not a good thing because it burns. UVA is also not harmless and too much of both can prematurely age the skin and increase the risk of skin cancers. So you do need to take care even if you find that the sun helps your skin. The people at highest risk are those who have fair or red hair and those who are freckled and whose skin does not tan easily.
What is UVB Treatment?
UVB contains a wide range of wavelengths and can be used to treat chronic plaque or guttate psoriasis, which has proved resistant to "topical" treatments (i.e. creams and ointments). In the past few years a more refined form of UVB has been developed, known as "narrowband" and this includes only the wavelengths that are considered most important in the clearance of psoriasis. Narrowband UVB phototherapy, often called TL-01, is highly effective in the treatment of psoriasis. The aim is to clear the skin and this usually takes up to approximately 30 treatments over a period of weeks. Treatment is generally administered in hospital using carefully controlled treatment courses supervised by trained staff. Many studies have shown narrowband UVB to be superior to broadband UVB for the clearance of psoriasis, with fewer treatments and less risk of sunburn-like adverse effects during treatment.
Narrow-band UVB can result in skin reddening (erythema), in a similar way to sunlight and broadband UVB. Frequent emollients should be applied to skin erythema, and if recommended by the therapist, topical steroids. UVB can sometimes provoke polymorphic light eruption in susceptible people – this is a very common form of light sensitivity, often confused with “prickly heat” – but this does not generally require the light therapy to be stopped, often lowering the dose or using a topical steroid will be sufficient. Long term exposure to natural or artificial ultraviolet radiation ultimately is likely to increase your risk of skin ageing and skin cancer. However, preliminary studies of the long term risks of narrowband UVB have, to date, shown no significant association with skin cancer in patients treated with UVB alone, suggesting it is no more risky than broadband UVB. However, cautious interpretation of these data is needed as longer term follow up is required. In general this needs to be considered when deciding on a phototherapy treatment course and 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 of course vary from person to person depending on factors such as skin type and the potential benefit:risk of other alternative therapies that would be considered if phototherapy was not an option.
What does the treatment involve?
Most patients attend three times (can be two to five times) weekly. The patient is placed in a specially designed cabinet containing fluorescent light tubes. The patient stands in the centre of the cabinet, undressed except for underwear (and if your psoriasis is in the genital and buttocks area then a sock for men is sometimes advised...or a thong for women), and wears protective goggles. Usually the whole body is exposed to the UVB for a short time (seconds to minutes). The amount of UV is carefully monitored in terms of treatment numbers and doses. A standard regime is generally used although there may be variations in protocols depending on factors such as the individual's skin type and type and severity of psoriasis. The skin may remain pale or turn slightly pink after each treatment. Let your therapist know if you experience any discomfort. Patches of psoriasis generally start to become thinner after five to ten treatments. Most patients with psoriasis need about 15-30 treatments to clear.
How much UVB can people have in one lifetime?
We do not have firm data to give an answer to this question. Some individuals are more susceptible to the damaging effects of UV than others – so particular care is needed if you have fair/red hair, freckles and don’t tan. In general limiting an individual’s exposure to UVB is essential – for example, if your psoriasis does not affect your face then you should wear a face shield during treatment. Although the preliminary findings for narrowband UVB have not shown a significant association with skin cancer, in the absence of longer term data, it has been predicted, based on mathematical models, that proceeding beyond 450 treatments with narrowband UVB for a patient receiving one treatment course per year with the face unshielded should be with particular caution. Detailed records of treatment numbers and exposure doses and follow-up skin checks of patients considered to be at particular risk are essential. Clearly weighing up risks of other potential therapies and taking the patient’s own informed views into account will be an important part of the decision-making process.
What I found helped me when I did UVB
I arranged to have my blasts at about 9am 3 times a week and so I was able to have a bath and moisturise really well with Vaseline Lotion before I left the house...apparently this helps to maximise the benefits of the UVB. Then in the evenings I had another bath but put in 4/5 capfuls of Polytar emollient and soaked for 20 mins. Before going to bed I applied Dovonex to the affected areas. I also drank loads of water and tried to avoid alcohol for a few weeks. At the weekends I'd sometimes have 2 Polytar baths ...maybe I was just addicted to coal tar...
To UVB or not to UVB?
There are large numbers of studies showing the positive effect of UVB on Psoriasis patients. Generally approximately 80% of patients will be cleared within 6-8 weeks, with 3 treatments per week. Maintenance therapy is generally not recommended – the approach is clearance courses of phototherapy and in patients whose psoriasis relapses rapidly other adjunctive or alternative therapies may be required.
There are many threads and posts, including questions and answers perhaps not dealt with above and experiences of those PHO UK members who have had or are having UVB, in the forums
Guy June 2003 - Updated by the British Association of Dermatology Jan 2010