Henoch–Schönlein purpura is a disease that belongs to the group of vasculitides. The disease in children is usually mild, but if it occurs in adulthood it can bring many adverse consequences. In mild forms, the major manifestation is skin lesions. The disease may also affect the joints, kidneys, gastrointestinal tract and lungs. The aim of the study is to present the differences in the course and prognosis of Henoch–Schönlein purpura in children and adults, the diversity of aetiological factors of IgA-associated vasculitis as well as clinical implications and diseases concomitant with purpura. Typically, it is believed that viral and bacterial agents induce Henoch–Schönlein purpura. Vaccination is one of the stimuli which can cause IgA-associated vasculitides. The coexistence of Henoch–Schönlein purpura with neoplasms is another interesting issue. The appearance of purpura may indicate a metastasis or recurrence. In adults, the course of Henoch–Schönlein purpura is much more severe – up to 75% of adults who have developed it have gastrointestinal complications. Renal complications occur in up to 87% of adult patients. Pain in the hip joints in the course of Henoch–Schönlein purpura may be a manifestation of necrosis of the femoral head. There are also described cases of complete myocardial infarcts or only its clinical signs. Epididymitis and scrotal oedema are complications of boys and men who have developed purpura. The occurrence of Henoch–Schönlein purpura in males older than 50 is associated with a worse prognosis. Patients with recurrent vasculitis should be carefully evaluated for the presence of a neoplasm.