Increased Systemic Symptoms in Patients with Positive Direct Immunofluorescence of Skin Biopsies With Henoch–Schonlein Purpura/IgA Vasculitis: A Retrospective Chart Review

To the Editor: IgA vasculitis, formerly known as Henoch–Schonlein purpura, is an immune-mediated vasculitis characterized by perivascular IgA deposits in small vessels.1 These deposits result in palpable purpura, often with other systemic manifestations such as arthritis/arthralgias, abdominal pain, or glomerulonephritis.1 Although IgA vasculitis is more common in children, when present in adults, is more severe.2 Management of IgA vasculitis is particularly challenging as the initial severity of presentation rarely mirrors the long-term clinical course when it comes to end-stage renal complications.2 Direct immunofluorescence (DIF) of skin biopsies is an important tool in the diagnosis of IgA vasculitis.3 The published work suggests that there is an increase in systemic symptoms in patients with positive DIF on skin biopsies in patients with IgA vasculitis. This study was performed by conducting a retrospective chart review of patients seen at the University of Miami between 2014 and 2019. A total of 92 charts were reviewed. Thirty six met the clinical criteria for IgA vasculitis/HSP and of those 36 patients, 22 patients had a DIF performed. Pediatric patients were excluded from this study (Figs. 1, 2).FIGURE 1.: Methodology for chart review.FIGURE 2.: Percentage of symptoms present in patients positive for IgA on biopsy.A total of 14 of the 22 patients (63.63%) had positive DIF of a skin biopsy, with IgA being the predominant immunoreactant. Of the patients who were positive for IgA on biopsy, 64.3% reported gastrointestinal symptoms, 28.6% had musculoskeletal involvement, and 14.3% reported fever. Thirty eight percentage of patients with positive IgA DIF had hematuria, 36.4% had proteinuria, and 21.4% had increased Cr. Serum IgA levels were increased in 57.1% of patients with positive IgA on DIF (from a total of 7). Interestingly, 5 of 14 patients (28.6%) who were IgA positive on DIF did not experience any systemic symptoms, such as fever or gastrointestinal, musculoskeletal, or renal symptoms. Of these 5 patients, 1 patient did develop renal abnormalities with proteinuria on urinalysis. In our study, we demonstrate a positive correlation between systemic symptoms and IgA deposition. However, 28.6% of patients with IgA vasculitis lacked typical systemic symptoms and were diagnosed based on DIF findings alone. In addition, one of these 5 patients developed renal involvement. Given these findings, we recommend performing DIF on all patients with vasculitis to evaluate for the presence of IgA, even in the absence of other suggestive features for IgA vasculitis, due to the higher risk of renal involvement observed in our study. Jennifer Ko et al4 described the use of DIF for HSP. In this study, when HSP was not suspected but there was concern for vasculitis only 1/163 cases had positive IgA. In cases where HSP was suspected, 27/95 cases has positive IgA on DIF.4 However, our findings demonstrate higher rates, with 5 patients without suspicion for HSP testing positive for IgA on DIF, of the cohort of 22 total patients. Although the financial cost of DIF can be significant, DIF has the potential to guide aggressive clinical monitoring early in the clinical course of IgA vasculitis as clinical severity at initial presentation rarely mirrors the long-term clinical course of the disease and sequela, justifying the expense. A limitation of this study was the sample size, and an avenue for further investigation would be applying findings from this study to a larger population to better understand the pathophysiology of HSP/IgA vasculitis.