Isotopic Responses Following Herpes Zoster

August 2025 | Volume 24 | Issue 8 | 9252 | Copyright © August 2025


Published online July 30, 2025

doi:10.36849/JDD.9252

Olivia M. Burke BSa, Betty Nguyen MDa, Jacob Beer MDa,b, Jose A. Jaller MDa*, Scott A. Elman MDa*

aDr. Phillip Frost Department of Dermatology & Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL
bBeer Dermatology, West Palm Beach, FL

Abstract
Background: Herpes zoster (HZ) typically resolves without sequelae, but rare chronic dermatologic complications can develop at the site of prior infection, termed an isotopic response. This phenomenon involves the emergence of a new, unrelated skin disease in the area previously affected by HZ.
Objective: To describe 2 cases of autoimmune skin conditions, discoid lupus erythematosus (DLE) and bullous pemphigoid (BP), emerging as isotopic responses following HZ infection, and to discuss possible pathophysiologic mechanisms.
Cases: Two patients with a history of HZ presented with persistent or recurrent cutaneous lesions localized to the previously affected dermatomes. Clinical evaluation, histopathology, immunologic testing, and PCR were performed to exclude viral persistence and con-firm autoimmune etiology.
Case 1: A 51-year-old woman with systemic lupus erythematosus (SLE) developed chronic plaques in a dermatomal distribution six months after HZ. Histology confirmed DLE. Restarting systemic immunosuppression and topical corticosteroids led to clinical improve-ment.
Case 2: A 65-year-old woman developed a chronic blistering eruption two years after HZ in the same location. Biopsy and immunofluo-rescence confirmed BP. She responded well to localized high-potency corticosteroid therapy.
Conclusion: These cases underscore the diagnostic importance of recognizing Wolf’s isotopic response, in which autoimmune skin conditions may manifest at sites of prior HZ. Clinicians should maintain a high index of suspicion for autoimmune etiologies in persis-tent post-HZ eruptions, especially in patients with underlying autoimmune diseases.

J Drugs Dermatol. 2025;24(8): doi:10.36849/JDD.9252

INTRODUCTION

Herpes zoster (HZ), caused by the reactivation of the varicella-zoster virus, typically resolves without long-term sequelae. However, chronic dermatologic complications can emerge at the site of prior infection, a phenomenon known as an isotopic response.1 A wide spectrum of dermatologic conditions has been reported with isotopic response, highlighting its diverse clinical manifestations. Herein, we present 2 cases of bullous pemphigoid and discoid lupus erythematosus to underscore this variability and expand awareness of this phenomenon.

Case 1
A 51-year-old woman presented with a six-month history of a persistent rash following an episode of HZ. Her medical history was notable for SLE with lupus nephritis, hypothyroidism, and psoriasis vulgaris. During her HZ episode, she was treated with antiviral therapy, but her SLE medications, prednisone and mycophenolate mofetil (MMF), were held. She remained on hydroxychloroquine 400 mg daily. The patient endorsed chronic dry eyes and intermittent stabbing pain in the affected skin areas. On examination, the rash consisted of multiple pink, brown papules coalescing into plaques overlying the midline of the back extending anteriorly to the right breast in T1-T4 dermatome (Figure 1). A skin biopsy revealed basal vacuolar alteration, and superficial and deep perivascular and periadnexal lymphocytic infiltrate. Viral cytopathic changes were absent, supporting the diagnosis of DLE rather than
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