Isotopic Responses Following Herpes Zoster

Area of Science:

• Dermatology
• Immunology
• Infectious Disease

Background:

• Herpes zoster (HZ) usually resolves without lasting effects.
• Rarely, chronic skin conditions can arise at the prior HZ site, termed an isotopic response.
• This involves a new, unrelated skin disease appearing in the HZ-affected area.

Purpose of the Study:

• To report two cases of autoimmune skin conditions (discoid lupus erythematosus and bullous pemphigoid) as isotopic responses after HZ.
• To explore potential pathophysiologic mechanisms behind these occurrences.

Main Methods:

• Two patients with HZ history presented with localized, persistent skin lesions.
• Diagnostic methods included clinical evaluation, histopathology, immunologic testing, and PCR.
• Viral persistence was excluded, and autoimmune etiology was confirmed.

Main Results:

• Case 1: A patient with SLE developed discoid lupus erythematosus (DLE) post-HZ, responding to immunosuppression and topical steroids.
• Case 2: A patient developed bullous pemphigoid (BP) post-HZ, responding to potent topical corticosteroids.
• Both cases showed autoimmune skin conditions localized to prior HZ dermatomes.

Conclusions:

• These cases highlight the importance of recognizing Wolf's isotopic response.
• Autoimmune skin conditions can manifest at sites of prior HZ infection.
• Clinicians should suspect autoimmune causes for persistent post-HZ eruptions, especially in those with existing autoimmune diseases.