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Abstract: PO1784

Coexistence of Bullous Pemphigoid and Membranous Nephropathy

Session Information

Category: Trainee Case Report

  • 1202 Glomerular Diseases: Immunology and Inflammation

Authors

  • Thomas, Brigette, Florida Atlantic University Charles E Schmidt College of Medicine, Boca Raton, Florida, United States
  • Chaudhary, Dhishna, Florida Atlantic University Charles E Schmidt College of Medicine, Boca Raton, Florida, United States
  • Bethel, Anika, Florida Atlantic University Charles E Schmidt College of Medicine, Boca Raton, Florida, United States
  • Okpokpo, Enoemem M., Florida Atlantic University Charles E Schmidt College of Medicine, Boca Raton, Florida, United States
Introduction

Bullous pemphigoid (BP) is an autoimmune disease with linear deposition of IgG and C3 in the skin basement membrane. BP is rarely associated with renal abnormalities like membranous glomerulonephropathy (MN). We describe a rare case of MN in a patient with BP.

Case Description

75-year-old male, intermittently treated with prednisone for upper extremity (UE) skin lesions, presents with bilateral UE pruritic bullae, bilateral lower extremity (LE) and scrotal edema. He was previously treated for LE edema. Renal indices confirmed nephrotic range proteinuria. Kidney biopsy showed subepithelial immune deposits consistent with primary MN (immunostain negative for PLA2R). He was treated with furosemide and lisinopril. Skin biopsies of his bullae were inconclusive. His LE edema and UE bullae progressed due to lack of follow up, leading to this hospitalization. Labs revealed eosinophilia, hypoalbuminemia and nephrotic range proteinuria. HIV, hepatitis panel, ANA, SPEP and UPEP were negative. Malignancy was ruled out. Diagnosis of BP was finally confirmed via positive indirect immunofluorescence and ELISA testing. Treatment was limited to ethacrynic acid since ACEi/ARBs and furosemide are known to induce BP. Initiation of prednisone and rituximab resulted in cessation of new bullae and decrease in proteinuria.

Discussion

Both BP and MN are immune complex diseases involving two different basement membranes, so their occurrence together is not coincidence. Although our patient’s kidney biopsy had negative immunostaining, the electron microscopy identified only subepithelial deposits, characteristic of primary, not secondary MN. This coincides with few cases in literature identifying BP occurring exclusively with primary MN. Our patient developed BP manifestations prior to MN and received intermittent prednisone without formal diagnosis of BP. Perhaps corticosteroids suppressed his MN symptoms leading to delay in diagnosis. Improper treatment of MN with known BP inducing medications led to persistent bullae formation. As the severity of skin lesions decreased, so did the proteinuria, suggesting that progression of bullae may be a sign of worsening MN. This case highlights the importance of thorough history taking, detail review of medications and appropriate outpatient follow up.