A boy with diagnostically unclear vasculitis was described, in which development of the disease points out the presence of cutaneous form of poliarteritis nodosa. Nevertheless, there are also signs for systemic form of the disease. His symptoms are marked cutaneous eruptions of the livedo reticularis type, recidives of erythema nodosum on the limbs and trunk, even on the cheeks, sometimes accompanied with fever, arthralgias, myalgias and cutaneous ulcera on the places of mechanical pressure (elbows), but also with monotopic ventricular premature beats and sporadic microhaematuria. Clinical development of the disease and differential diagnosis exclude other autoimmune disorders with great probability. The positive finding of cANCA has pointed out the diagnosis of vasculitis. Microscopical analysis of the skin didn't reveal any pathological changes. In the boy's disease is interposed a streptococcal infection, and maybe, tuberculosis. The paper deals with wide spectrum of diseases in differential diagnosis, and also with a possible role of bacterial superantigens in the genesis of autoimmunity.