How to diagnose allergic purpura

The earliest diagnostic criteria, according to the American Rheumatological Association, included four points: palpable purpura; second, onset at age less than 20; third, acute abdominal pain; and fourth, skin biopsy showing neutrophil infiltration of arterioles or venules. Two of these four points were met and the diagnosis was /confirm/ied. The most recent is a new European diagnosis of cutaneous purpura, not accompanied by thrombocytopenia or coagulation disorders, accompanied by one or more of the following manifestations, there are diffuse abdominal pain, arthritis and arthralgia, tissue biopsy shows IgA mainly immune complex deposition, that is, as long as the platelets are normal purpura rash, accompanied by arthralgia can be diagnosed simply.