Rising Proteinuria in IgA Vasculitis: A Trial That Answered the Wrong Question for This Point in the Disease
The purpura and joint pain have already improved on their own. What hasn’t improved is a proteinuria trend the team can’t agree whether to treat, watch, or biopsy first.
Theo B. is a 7-year-old boy who came in ten days ago with the pattern his pediatrician recognized immediately — palpable purpura across both buttocks and the backs of his legs, colicky abdominal pain that came and went over two days, and migratory swelling in both knees that made him refuse to walk to the bus stop one morning. The purpura and joint pain have both improved substantially since then without any specific treatment beyond rest and acetaminophen, following the self-limited course IgA vasculitis usually takes in children his age. A urinalysis sent on day three, done as routine screening rather than because of any specific renal symptom, showed microscopic hematuria and 400 milligrams of protein per 24-hour equivalent — a real but modest finding, well short of nephrotic range.
A repeat urine collection three days later showed the protein had risen to 900 milligrams, still short of the nephrotic threshold but a genuine upward trend rather than a stable, incidental finding. His blood pressure has stayed normal throughout, his creatinine remains within the normal range for his age, and he has had no gross hematuria at any point — reassuring on their own terms, but none of them speak directly to whether the trend itself is heading somewhere that matters. The largest placebo-controlled trial on early corticosteroid use in this disease, run by Dudley and colleagues, showed that prednisolone given early in the illness course did not prevent progression to nephritis or shorten the time to resolution — a genuinely negative result that reshaped how liberally steroids are now offered in this disease's early phase, but one that enrolled children with new-onset disease and minor or absent kidney involvement — which is what Theo was on day three and is no longer on day six. The trial is not wrong about him; it stops short of him. What it can still say is that nothing in the strongest evidence available licenses treating a rising number on its own. What it cannot say is anything at all about a number that has already risen.
A trial that answered a different question than today’s
Four hundred to nine hundred milligrams in three days is a real trajectory, not noise. Consensus recommendations from groups like SHARE support treating IgA vasculitis nephritis once proteinuria crosses recognized thresholds, specifically because waiting through a worsening trend risks losing an earlier intervention window in glomerular disease. I'd start corticosteroids now rather than wait to see how much higher this climbs.
I want to name the trial everyone's implicitly reasoning around: Dudley's placebo-controlled study found early prednisolone did not prevent progression to nephritis or change outcomes when given prophylactically. That result is part of why we don't reflexively start steroids in every HSP case anymore.
I'll grant that trial tested prevention, not treatment of nephritis already three days into a rising trend — it doesn't directly answer today's question. But its broader lesson, that this disease has historically been over-treated with steroids relative to what the evidence actually supports, should make us cautious about treating a short trend rather than a confirmed, sustained pattern.
I think you're both arguing from indirect evidence — a trend line on one side, a trial that didn't test this exact question on the other — when there's a more direct answer available. A renal biopsy would tell us whether this is mesangial-predominant disease, which usually resolves on its own regardless of what we do, or a crescentic pattern, where the case for treating now gets much stronger.
His renal function is normal and he has no gross hematuria, so a biopsy isn't urgent tonight. But I'd rather have that histology in hand before either starting steroids on a trend or committing to watch through a proteinuria climb we can't yet interpret with confidence.
A renal biopsy was scheduled for later that week, with continued urine monitoring in the interim and no corticosteroids started before the histology result — the team's way of resolving the disagreement with more direct evidence rather than choosing between the trend and the trial on inference alone.
Not agreed, and named explicitly rather than papered over: if the biopsy shows mesangial-predominant disease with no crescents, the Pediatric Rheumatologist would treat that as reassurance to continue observation even with proteinuria still elevated, while the Nephrologist would still want to see the trend itself plateau or reverse before fully standing down, regardless of a reassuring biopsy. Both agreed the biopsy result changes the conversation meaningfully either way; neither agreed in advance on exactly how much.