People with psoriasis can be treated at home safely and effectively with phototherapy, Dutch researchers say.

Psoriasis is a common inflammatory skin condition that causes red, scaly patches. If affects about one million Canadians, according to Psoriasis Support Canada.

Treatment often involves going to the hospital three times a week for eight to 10 weeks for ultraviolet B (UVB) phototherapy that helps dampen down the immune overreaction in the skin.

Home-based phototherapy has been available since the late 1970s, but some dermatologists were concerned that the home treatments could be inferior or riskier. The equipment is similar to a tanning bed but uses a different wavelength.

In this week's issue of the British Medical Journal, Mayke Koek of the University Medical Center Utrecht and colleagues compared 196 psoriasis patients who were randomly selected to use a UVB unit at home or to receive the treatment at a hospital.

The proportion of patients who achieved a 50 per cent or more reduction in their scores for psoriasis area and severity was 82 per cent for those treated at home compared with 79 per cent in hospital, the researchers found.

The total doses of ultraviolet B light were similar and short-term side-effects also did not differ.

People who were treated at home said the burden of undergoing the therapy was significantly lower, and they were more likely to report the experience as excellent (42 per cent) compared with those treated as outpatients (22 per cent).

Costly devices need to be maintained

Experience in Germany, the U.S., the Netherlands and Scotland confirm that home based UVB phototherapy would be feasible and practical, but the cost differences need to be weighed, Prof. Alex Anstey of the department of dermatology at Royal Gwent Hospital in Newport, Wales, said in a journal commentary accompanying the study.

Home-based units are available in Canada. Patients pay $10, 000 out of pocket for the devices, which are not covered by insurance plans, said Dr.Yves Poulin, president-elect of the Canadian Dermatology Association and a clinical professor in the department of medicine at Laval University in Quebec City.

In general, Poulin said, he has found better results from using the devices in hospital, where the bulbs are changed regularly, nurses monitor the dose and the treatments are covered by provincial health plans.

"Let's say you buy [an exercise] bike," Poulin said. "You have it in your house, and you use it for a while and then it goes in the wardobe. [The device] has to be maintained, it has to be calibrated. People tend not to do that in the long term. That's a drawback."

Regardless of where the devices are found, phototherapy does not address the joint component of psoriasis, he noted.