Suggest Treatment For HSP Accompanied With Swelling And Pain In The Knees

My four year old has welts/bruising spots on his legs (maybe 6 places ranging in size from a pea to quarter. He also had some blood in his urine and recurrent abdominal pain. The pediatrician said it was HSP. Tonight his knee has become very very swollen, he cries out if I try to move him (he has a very high pain tolerance) and he can t leave the couch. The on call pediatrician is not concerned but I am.....