Phototherapy has been around for decades
A specialist light treatment for psoriasis is just as effective and safe when given at home as in hospital, say Dutch researchers.
Phototherapy using UVB light is rarely used in the UK because of limited availability and the number of hospital visits required.
But a study of 200 patients found the same results with home treatment.
One UK expert said the British Medical Journal study highlighted an important treatment gap in psoriasis care.
Psoriasis is a common disorder caused by too rapid production of new skin cells, causing red scaly patches.
Up to 3% of the UK population is affected by the non-contagious condition which can cause significant disability.
For those who have access to UVB treatment at their local dermatology unit, a course usually entails three visits each week for between eight to 10 weeks.
It works by dampening down the immune overreaction in the skin.
One reason that the treatment is usually done in hospital is because most dermatologists believe that home phototherapy is inferior and that it carries more risks.
In the latest study, patients with psoriasis from 14 hospital dermatology departments were randomly assigned to receive either home UVB phototherapy or hospital-based treatment.
Home treatment was equivalent to hospital therapy both in terms of safety and the effectiveness of clearing the condition.
And those treated at home reported a significantly lower burden of treatment and were more satisfied.
Study leader Dr Mayke Koek, from Utrecht University Medical Centre, said: "We knew a lot of dermatologists are not convinced of the safety and effectiveness of UVB phototherapy but our theory was they should be equally safe."
"One of the most important findings was a lot of patients treated at home were more satisfied."
Professor Alex Anstey from the Royal Gwent Hospital in Newport, Wales, said with the exception of Scotland, phototherapy in the UK was limited to people who lived near a big hospital.
"In my area there are very large numbers of people who don't have access to phototherapy which is a shame as it's a very effective and safe treatment."
He said that the equipment - similar to a tanning bed, but a different type of light - costs between £5,000 and £10,000 but was very cheap compared with some of the new biological therapies in use and could be lent to patients for the duration of their treatment.
Gladys Edwards, chief executive of the Psoriasis Association, said the guidelines on treating psoriasis should be reviewed in light of the new research.
"Patient choice is important and for some patients managing their UV treatment at home would clearly be preferable.
"It is crucial, however, that there is absolutely clear guidance and information on when this is appropriate and how it should be managed for patients and clinicians."