Joan is a 15-year-old girl who complained of a purpuric rash over both lower limbs with bilateral ankle pain and abdominal pain for 4 days. She was diagnosed with Henoch-Schönlein purpura. Her initial blood test, including a routine urine test, was normal. Her arthritis progressed to affect both knees, and the purpuric rash became more extensive. Her abdominal pain was getting worse. Her abdominal ultrasound was normal. Because of the progression of vasculitis, she was treated with a short course of oral Prednisolone and tapered off in 2 weeks. However, a few days after taking off the steroid, she got another relapse of purpuric rash and abdominal pain. She was treated with another short course of oral Prednisolone and tapered again, yet she had a third relapse, but the symptoms were less severe. She was managed conservatively. However, her urine started to show microscopic haematuria and proteinuria. The proteinuria increased to >0.5 g/day. Her blood test for immunological markers, including antinuclear factor, anti-dsDNA, ANCA, anti-ENA, complements, ASOT, immunoglobulin pattern, hepatitis B and hepatitis C, were all negative. Her skin biopsy confirmed leukocytoclastic vasculitis with predominantly IgA deposition, compatible with Henoch-Schönlein purpura. How would you manage Joan’s problem?