UV-B Phototherapy Clears Psoriasis Through Local Effects

Abstract

Objective: To determine if UV-B phototherapy clears psoriasis through systemic effects.Design: Randomized, within-subject comparison of change in psoriasis in 3 plaques in patients attending for whole-body UV-B therapy. Change in patients' psoriasis plaques covered during UV-B treatment was compared with plaques in an untreated control group.Setting: University hospital phototherapy unit. Patients:The study population comprised 17 patients with chronic plaque psoriasis treated with UV-B and 24 psoriasis control patients awaiting UV-B phototherapy.Interventions: Treatment with a standard 3-times weekly narrowband TL-01 UV-B regimen. Three similar plaques were randomly allocated to be covered every treatment, covered for 2 of 3 weekly treatments, and exposed to local UV-B every treatment. Similar plaques were selected in control patients (awaiting but not yet started UV-B therapy). Severity of psoriasis plaques was assessed using a scaling, erythema, and induration (SEI) scoring system.Main Outcome Measures: Change in SEI score of the selected plaques over the complete treatment course for UV-B-treated patients and change over 3 weeks in SEI score of plaques covered during UV-B treatment compared with that of plaques in controls.Results: There was a significant (PϽ.001) difference in how much the SEI score changed in the 3 plaques in UV-B-treated patients. It fell by a mean of 7.6 for uncovered plaques compared with 3.2 for plaques covered during each UV-B exposure (95% confidence interval for difference, 3.0 to 5.8). In patients awaiting UV-B, SEI score of plaques fell by a mean of 0.4 over 3 weeks, compared with a mean fall of 1.4 for covered plaques in UV-B-treated patients (95% confidence interval for difference in means, 0.1 to 2.0). Conclusions:If UV-B therapy has any systemic effect capable of improving psoriasis, this effect is small and unlikely to be of clinical importance. It is insufficient to alter interpretation of findings of within-subject comparative phototherapy studies. UV-B phototherapy works for chronic plaque psoriasis through local effects.

Randomized Double-blind Trial of the Treatment of Chronic Plaque Psoriasis

“…In such studies it is possible that the effect of treatment on one side is transmitted to the other, thereby minimizing the difference between the 2 sides, but any such effect is likely to be small. 18 One of these studies 2 found slight differences in favor of PUVA, but they were not statistically significant. Another study, 3 in which bath PUVA was used, showed a higher clearance rate with NB-UVB, although the median number of treatments to clearance was lower in the PUVA group.…”

Phototherapy with Narrowband vs Broadband UVB

“…In the case of psoriasis, nUVB seems to clear plaques through local rather than systemic effects, as unexposed plaques cleared significantly less than directly exposed plaques (35). However, it has also been hypothesized that clearing of psoriasis is a combination of local and systemic effects (36).…”

Treatment of psoriasis in patients with hepatitis C: From the Medical Board of the National Psoriasis Foundation

“…Several clinical trials have determined that the systemic effects of UVB therapy are unlikely to be of clinical importance in patients with or without HCV, but potential long-term effects have yet to be uncovered. [21][22][23] Psoralen plus UVA Another phototherapy, which includes the combination of exposure to UVA and ingestion of a psoralen photosensitizer, has shown to induce a longer remission period of disease. No studies have been done in patients with psoriasis and HCV receiving PUVA.…”