A crack in the armor: Wolf isotopic response manifesting as cutaneous lupus.

Wolf isotopic response represents the development of skin lesions of one particular morphology occurring at the same site as another morphologically distinct and unrelated skin lesion. Cutaneous lupus erythematosus (CLE) is an autoimmune connective tissue disorder encompassing a wide range of phenotypes that may be associated with systemic involvement. Although CLE is a well-described entity with a broad spectrum, the occurrence of lesions manifesting as an isotopic response is rare. We present a patient with systemic lupus erythematosus who developed CLE in a dermatomal distribution following herpes zoster. When CLE lesions present in a dermatomal distribution, these cases may be difficult to distinguish from recurrent herpes zoster infection in an immunosuppressed patient. Therefore, they pose a diagnostic challenge and require balancing antiviral therapy with immunosuppression to sufficiently maintain adequate control of the autoimmune disease while addressing possible infections. To avoid treatment delay, clinicians should have elevated suspicion for an isotopic response when disparate lesions erupt in areas previously affected by herpes zoster or in cases of persistent eruptions at sites of prior herpes zoster. We discuss this case within the context of Wolf isotopic response and review the literature for similar cases.