Bullous Pemphigoid with Atypical Skin Lesions and Acute Interstitial Nephritis: A Case Report and Focused Literature Review

Abstract

Patient: Male, 76 Final Diagnosis: Drug induced bullous pemphigoid Symptoms: Skin rash Medication: Cephalexin Clinical Procedure: Skin biopsy Specialty: General and Internal Medicine Objective: Unusual clinical course Background: The hallmark of bullous pemphigoid (BP) is widespread tense blisters arising on normal or erythematous skin, often with marked pruritus, the diagnosis of which is confirmed by direct immunofluorescence (DIF). BP is an autoimmune process that can be induced, though rarely, by medications. Drug-induced BP often has atypical clinical presentation, which requires a good understanding of other dermatological conditions with similar presentations, in particular, bullous subtype of erythema multiforme. End organ involvement warrants differentiating it from one of the severe cutaneous adverse reaction (SCAR) syndromes. Case Report: A 76-year-old African American male presented with extensive targetoid purplish skin lesions that clinically resembled atypical erythema multiforme, and one tense blister that raised a concern for BP. The patient presented 6 weeks after treatment with cephalexin for a urinary tract infection. Initial workup showed serum eosinophilia, acute kidney injury and eosinophiluria requiring deliberations on SCAR syndromes. A skin biopsy at an intralesional location showed a negative DIF, however, a skin biopsy at a perilesional site showed a positive DIF, confirming the diagnosis of BP. Conclusions: This case demonstrates an atypical presentation of BP induced by drugs. It emphasizes the need for a greater level of awareness of diagnosis and treatment of the various entities that fall under adverse drug reactions in the elderly. It also highlights the need for appropriate choice of skin biopsy techniques (intralesional versus perilesional) to avoid misdiagnosis, as well as lessons on how to approach dermatologic conditions with end organ involvement for hospitalists and other medical professionals who routinely deal with undifferentiated disease conditions.

Valsartan‐associated bullous pemphigoid initially presenting as erythema multiforme

“…Only 10 cases of EMBP have been reported in the English literature. 2,3 Most patients (including our case) had no mucosal involvement, and it was controlled within 1 month after cessation of predisposing factors.…”

Acute Tubulointerstitial Nephritis in a Patient on Anti-Programmed Death-Ligand 1 Triggered by COVID-19: A Case Report

“…9 In this case, ATIN occurred 3 years after starting immunotherapy, although treatment was temporarily interrupted for cutaneous toxicity. It is important to note, however, that drug-induced bullous pemphigoid has been associated with acute interstitial nephritis 10 and may indicate increased individual susceptibility to autoimmune toxicities. Note.…”

Atypical Bullous Pemphigoid After Linagliptin Intake

“…To date, few articles have assessed the association between atypical bullous pemphigoid and linagliptin intake. However, as reported by Ganapathineedi et al, atypical presentation of bullous pemphigoid occurred in a patient taking cephalexin for a urinary tract infection; the patient had one blister and a diffuse symmetrical erythema on his body, sparing the face and oral mucosa [ 16 ].…”