P G Calzavara-Pinton1. 1. Dermatology Department, Brescia University Hospital, Italy.
Abstract
BACKGROUND: Metal-halide lamps (MHLs) and fluorescent lamps (FLs) are widely employed for PUVA therapy of psoriasis, but they have never been compared in a clinical trial. OBJECTIVE: We studied the irradiance, spectral power distribution, irradiation field and efficacy of two cabinets with standard FLs or MHLs with a new UVA filter. METHODS: The photophysical properties of the lamps were studied with a spectroradiometer. After phototesting, 22 patients with recurrent plaque type psoriasis were treated in a stand-up irradiation cubicle housing 27 standard FLs, and, at recurrence, in a cubicle with 15 MHLs. When indicated, lesions of the legs underwent supplementary exposures with small FL or MHL devices. RESULTS: MHLs had a greater emission in the longer UVA wavelengths than FIs. The MHL cubicle had a greater irradiance and a more uniform output along the vertical axis. Both cubicles were effective in a similar number of exposures. However, FLs were more phototoxic and lower cumulative UVA doses were administered although the total duration of exposures was longer. Eleven patients treated with FLs and 7 patients with MHLs required supplementary treatments of the legs. The number, cumulative UVA dose and total duration of these exposures were significantly greater with FLs. CONCLUSION: Cabinets with MHLs increase the number of patients treated in the same time period and reduce the number of patients needing supplementary treatments of the legs. Cumulative UVA doses are greater with MHLs, but their emission is prevalent in the less erythematogenic and carcinogenic longer UVA wavelengths.
BACKGROUND:Metal-halide lamps (MHLs) and fluorescent lamps (FLs) are widely employed for PUVA therapy of psoriasis, but they have never been compared in a clinical trial. OBJECTIVE: We studied the irradiance, spectral power distribution, irradiation field and efficacy of two cabinets with standard FLs or MHLs with a new UVA filter. METHODS: The photophysical properties of the lamps were studied with a spectroradiometer. After phototesting, 22 patients with recurrent plaque type psoriasis were treated in a stand-up irradiation cubicle housing 27 standard FLs, and, at recurrence, in a cubicle with 15 MHLs. When indicated, lesions of the legs underwent supplementary exposures with small FL or MHL devices. RESULTS: MHLs had a greater emission in the longer UVA wavelengths than FIs. The MHL cubicle had a greater irradiance and a more uniform output along the vertical axis. Both cubicles were effective in a similar number of exposures. However, FLs were more phototoxic and lower cumulative UVA doses were administered although the total duration of exposures was longer. Eleven patients treated with FLs and 7 patients with MHLs required supplementary treatments of the legs. The number, cumulative UVA dose and total duration of these exposures were significantly greater with FLs. CONCLUSION: Cabinets with MHLs increase the number of patients treated in the same time period and reduce the number of patients needing supplementary treatments of the legs. Cumulative UVA doses are greater with MHLs, but their emission is prevalent in the less erythematogenic and carcinogenic longer UVA wavelengths.