Psoriasis vulgaris is a complex immune-mediated disorder that manifests as a chronic skin disorder characterized by well-circumscribed inflammatory erythematous plaques. As a chronic inflammatory systemic disease, psoriasis is associated with an extensive list of comorbid diseases, including renal involvement. In a recent case report, a 43-year-old male patient with generalized pustular psoriasis (GPP) presented to the nephrology department with a rapidly progressive decline in renal function. The diagnosis of GPP was made a month ago, secondary to a coagulase-negative staphylococcal superinfection. Essentially, this introduced a diagnostic challenge as the presumed diagnosis of immunoglobulin A (IgA) nephropathy had to be distinguished from IgA-dominant infection-related glomerulonephritis (IgA-IRGN). 

The most common way psoriasis affects the kidneys is through IgAN (immunoglobulin A nephropathy), which can cause a rapid decline in kidney function in rare cases. If skin or upper respiratory infection came before glomerulonephritis (GN), IgA-IRGN should be on the list of possible causes. Even though IgA-IRGN is more likely to show a rapid decline in renal function, IgAN can still show this symptom. A renal biopsy followed by immunofluorescence/electron microscopy analysis is the gold standard test to tell the difference between these two pathologies. More research is needed to discover specifics about therapy, prognosis and how psoriasis affects how a disease worsens.

Source: Klimko A, Toma GA, Ion L, et al. A case report of generalized pustular psoriasis associated with IgA nephropathy. Cureus. 2020;12(8):e10090.