Henoch-Schonlein purpura

MY WIFE, (70), WAS DIAGNOSED WITH SJOGRENS SYNDROME 3 YEARS AGO. SHE SUFFERS FROM DRY MOUTH & DRY EYES. THE DOCTOR PRESCRIBED PREDNISONE 5MG. TAB. WHICH HELP HER GAIN WEIGHT. (5' 2" 112# WENT DOWN TO 89# BEFORE SJOGRENS WAS DIAGNOSED) SHE'S NOW AT 112#, HOWEVER, ABOUT 6 MONTHS AGO SHE DEVELOPED A RASH ON HER FEET, THAT SPREAD UP TO HER KNEES, AND PARTIALLY TO HER THIGHS. HER FEET AND ANKLES WOULD SWELL UP, AND WAS ITCHY AND SLIGHTLY PAINFUL.
A DERMOTOLOGIST DIAGNOSED IT AS (Henoch-Schonlein purpura) AND GAVE HER A COUPLE OF SHOTS FOR THE INFLAMATION (inflammation), AND 6% SALICYLIC ACID CREAM TO PUT ON THE RASH, AND ORDER HER TO KEEP HER FEET ELEVATED FOR AT LEAST 20 MINS. A FEW TIMES A DAY. THIS HELPED, AND AFTER ABOUT 2 MONTHS THE RASH DISAPPEARED, AND SHE STOPPED USING THE CREAM. TWO WEEKS AGO THE RASH RETURNED, ITCHING, SLIGHT PAIN, (AS DID THE SWELLING OF HER FEET), (YESTERDAY). SHE'S USING THE CREAM AGAIN. WE INTEND  ON GOING TO THE DOCTOR AGAIN NEXT WEEK, HOPEFULLY HE CAN GIVE HER THOSE "SHOTS" AGAIN FOR THE SWELLING.
I READ SEVERAL ITEMS @ "Click here: Henoch-Schonlein purpura: Treatments and drugs - MayoClinic.com " WHERE IT MENTIONS BLOOD TESTS, AS WELL AS KIDNEY TESTS.
WE DO UNDERSTAND THAT THIS IS ALL CAUSED BY THE "SJOGRENS SYNDROME" AND USING THE  "PREDISONE" WHICH FALLS UNDER THE "MEDICATION: RISKS AND BENEFITS"
THE REASON FOR THIS ITEM IS TO TRY TO FIND OUT IF THERE MIGHT BE SOMETHING THAT THE DOCTOR THAT'S TREATING HER FOR THE "SJOGRENS" AND THE "DERMOTOLOGIST" MIGHT BE MISSING. (THEY EACH HAVE A LIST OF ALL THE MEDICATIONS SHE'S TAKING. I RECENTLY TOOK HER TO KIDNEY SPECIALIST THAT DID SOME TESTS, AND SAID THEY INDICATED HER KIDNEYS ARE WORKING AT 20% LESS OF WHAT THEY SHOULD BE WORKING FOR HER AGE.
SHE HAS LAB. WORKS, (BLOOD TESTS, ABOUT  EVERY 2 MONTHS, ALSO HAS HAD 24HR URINE TESTS, MRI / MRA OF THE KIDNEYS, ETC.
WOULD APPRECIATE ANY FURTHER INFORMATION.
FRANK