Acute Interstitial Nephritis (AIN): This condition is characterized by inflammation in the spaces between the renal tubules, often caused by an allergic reaction to medications (such as NSAIDs, antibiotics) or infections. Eosinophilia can be present due to the allergic nature of the reaction, and proteinuria is a common finding due to the renal damage.

Membranous Nephropathy: An immune-mediated condition leading to the thickening of the glomerular basement membrane, which can cause proteinuria. Eosinophilia might be seen in secondary forms of membranous nephropathy, especially those related to infections or drugs.
Minimal Change Disease (MCD): Although MCD is more commonly associated with nephrotic syndrome and selective proteinuria, some cases can present with eosinophilia, particularly if there's an allergic component to the disease.

Churg-Strauss Syndrome (Eosinophilic Granulomatosis with Polyangiitis, EGPA): A form of vasculitis that affects small to medium-sized vessels and is characterized by asthma, eosinophilia, and the presence of anti-neutrophil cytoplasmic antibodies (ANCA) in some cases. Renal involvement can lead to proteinuria.
Wegener's Granulomatosis (Granulomatosis with Polyangiitis, GPA): Another form of vasculitis that can affect the kidneys, leading to proteinuria. While eosinophilia is not a hallmark, it can be present, and missing this diagnosis could be catastrophic due to its potential for severe organ damage.

Eosinophilic Granuloma with Renal Involvement: Part of the spectrum of Langerhans cell histiocytosis, which can rarely involve the kidneys and present with proteinuria and eosinophilia.
Fibrillary Glomerulonephritis with Eosinophilia: A rare glomerular disease characterized by fibrillary deposits in the glomeruli, which can cause proteinuria. Eosinophilia in this context would be unusual but could be seen in specific cases.