Abstract: A method and apparatus for the treatment of psoriasis skin wounds are described. The method is based on the use of a short arc lamp having the capability of providing a narrow beam light source. The light source possesses a high intensity, the minimum irradiance applied being at least 1 mW/cm.sup.2 to be obtained by a light guide. The light guide is made from fused glass or an anaerobic liquid, with a diameter in the range of 2 to 10 mm and provides a transmittance of above 70%. The apparatus using this method, comprises a lamp selected from Xenon or Mercury-Xenon type, a glass lens, a black filter and a light guide having a diameter in the range of between 2 to 10 mm. It can be connected to a microprocessor, which by monitoring the time of treatment, delivers the correct dose of light.