Tc-99m pertechnetate radionuclide scrotal scanning was performed on nine hospitalized boys with anaphylactoid purpura and acute scrotal tenderness. Scrotal involvement in anaphylactoid purpura is generally a part of the basic pathological process (i.e., vasculitis). Sometimes testicular torsion could not be excluded by physical examination. Tc-99m radionuclide scan was proven to be a useful tool, enabling distinction between the two processes. In all the patients the scan showed increased flow to the scrotum, compatible with inflammation of the scrotal wall and normal testicular perfusion, ruling out testicular torsion. All the boys were treated conservatively, with rapid resolution of the scrotal symptoms.