Laser therapy that delivers a concentrated beam of ultraviolet light may help ease a hard-to-treat form of eczema, a small study suggests.

The study, published in the British Journal of Dermatology, compared the effects of laser therapy versus corticosteroid ointment in 13 patients with what is known as the prurigo form of atopic dermatitis.

Atopic dermatitis is a type of eczema, or skin inflammation, that arises from an allergic reaction; the prurigo form is marked by small, hard, intensely itchy nodules on the skin.

Only a small proportion of people with atopic dermatitis have the prurigo form, but the condition can be challenging to manage, according to Dr. Elian E.A. Brenninkmeijer, a dermatologist at the University of Amsterdam, in the Netherlands, and the lead researcher on the study.

The current findings, while based on only a small number of patients, suggest that when topical treatments fail to improve prurigo atopic dermatitis, laser therapy may be a suitable option, Brenninkmeijer told Reuters Health in an email.

Specifically, a device called the 308-nm excimer laser is approved in the U.S. for treating atopic dermatitis and certain other skin conditions, including psoriasis and vitiligo. It works by emitting a concentrated beam of ultraviolet B (UVB) light directly to patches of affected skin, avoiding the healthy surrounding skin.

UVB light has long been used to treat some cases of atopic dermatitis; it is thought to help by quelling the exaggerated immune response causing the skin inflammation. The purported advantage of the excimer laser over traditional UVB therapy is that it more precisely targets the problem areas of the skin.

However, there are only limited study data on the effectiveness of the laser therapy for atopic dermatitis, and almost nothing known about how it works for the prurigo form.

To investigate, Brenninkmeijer and his colleagues recruited 13 adults with atopic dermatitis and prurigo nodules on the upper or lower extremities on both sides of the body.

Over 10 weeks, the patients received twice-weekly laser treatments on one side of the body, and used prescription corticosteroid ointment - clobetasol propionate - on the other side of the body. Both the laser treatment and the ointment were applied directly to the prurigo nodules.

By the end of the treatment period, the study found, both therapies were similarly effective in reducing the number of skin nodules, inflammation and itchiness. All but one patient showed improvements; for three patients, the laser-treated side of the body showed greater improvements, while for four, the corticosteroid-treated side fared better.

However, the benefits of the laser tended to be longer lasting. Six months after treatment, eight patients had maintained a significant improvement on the laser-treated side, while only three showed similar results on the corticosteroid-treated side.

According to Brenninkmeijer, larger clinical trials are now needed to confirm the effectiveness of laser therapy for this form of atopic dermatitis, as well as its cost-effectiveness.

Topical corticosteroids have an obvious advantage in that they are inexpensive and convenient. But for people whose skin condition does not improve with topical treatment, Brenninkmeijer said, “the excimer laser might be a good alternative.”

The potential short-term risks of the laser therapy include burns (similar to a sunburn), blistering and skin darkening. Little is known about the possible long-term side effects, including whether there is any increase in skin cancer risk, according to Brenninkmeijer.

Researchers are still unsure whether traditional UVB therapy carries a heightened risk of skin cancer in the long term. It’s possible, Brenninkmeijer noted, that any such risk would be less with the excimer laser, since it targets only small areas of affected skin, but that remains to be seen.

SOURCE:  British Journal of Dermatology, online May 20, 2010.