The difference between simple purpura and allergic purpura is that simple purpura belongs to a subtype of allergic purpura, and allergic purpura also includes arthritic purpura, abdominal purpura and mixed purpura. Patients with simple purpura can take oral compound rutin tablets with calcium carbonate D3 tablets, patients with arthritic purpura can take oral rehmannia polysaccharide tablets, and abdominal purpura needs 654-2 to stop bleeding. In addition to the manifestation of petechiae and petechiae, arthritic purpura can also show positive manifestation of joint swelling and pressure pain of the extremities. Abdominal purpura can manifest as gastrointestinal bleeding and blood in stool, while mixed purpura has manifestations of both simple purpura and arthritic purpura or abdominal purpura.