Cutaneous vasculitis, secondary to drug reaction, infection or collage
n vascular disease, is the most common identifiable cause of palpable
purpura. Common causes of palpable purpura often can be identified dur
ing the patient's history and physical examination. When this conditio
n occurs in a patient who has not had a known precipitating event, or
when the cause is unclear from the history and physical examination, d
iagnosis may be based on findings of the laboratory investigations and
skin biopsy. Many cases of palpable purpura are idiopathic and self-l
imited. When treatment is necessary, dapsone, colchicine or systemic c
orticosteroids are useful drugs.