Patients with allergic purpura have characteristic purpuric skin rash and some of the following clinical manifestations may be present: migratory polyarthralgias or polyarthritis, colicky abdominal pain, nephritis. Because until now there is no satisfactory treatment, we applied low level laser therapy (LLLT) in order to compare it with the classical therapy. Thirty-one children (2-16 years of age) have been included in the study and treated at debut of the disease. They were randomly divided: group A - (15 children) received LLLT; group B (16 children) was administrated classical therapy. Two GaAlAs diode lasers in red and infrared region (670 nm and 830 nm) were used. The density of energy (4 - 10 J/cm2), irradiating frequency (2.4 Hz) - was applied one session daily, using scanning technique under a special treatment protocol on cutaneous purpuric areas (21 sessions). Very good results were obtained in laser group. In the control group, after an apparent improvement, subsequent exacerbations and remissions were present, and three children developed chronic renal disease. The results prove that LLLT is acting as a triggering factor, which induces systemic effects through the circulation, followed by a response of the children's entire immune system. That is why LLLT is a very promising modality of treatment for the allergic diseases in children.