Postherpes Zoster Keloid Formation: A Report of Wolf’s Isotopic Phenomenon

Dear Editor, Keloids arise from atypical wound healing following skin trauma or inflammation, influenced by genetic and environmental factors. They are more prevalent in individuals with darker skin tones, such as those of African, Asian, and Hispanic descent. The pathogenesis involves overactive fibroblasts generating excessive collagen and growth factors, evidenced by abnormal histologic findings. Clinically, keloids appear as firm, rubbery nodules extending beyond the initial injury site, differing from typical scars. Patients may experience pain, itching, or burning. Treatment options, including steroids, cryotherapy, surgery, radiotherapy, and laser therapy, vary in effectiveness, with no universal success. The management of keloids poses a multifaceted challenge.[1] Shingles, or herpes zoster, arises from varicella-zoster virus reactivation, dormant in sensory ganglia after prior chickenpox. In contrast to childhood chickenpox, shingles typically affects adults or the elderly. Zoster links to immune system inadequacy, allowing latent virus replication. Herpes zoster incidence correlates strongly with immune status, with high immunity protecting against shingles development. Despite resolving, the infection manifests in various ways and often leads to postherpetic neuralgia (PHN), causing lingering moderate-to-severe pain. This underscores the nonbenign nature of herpes zoster, even after initial resolution, and highlights the importance of immune defense in preventing its occurrence.[2] Here, we present the case of a 72-year-old male who, over the course of 3 months, developed progressively enlarging and pruritic keloids on his right thigh and buttock. One year earlier, he had been diagnosed with "herpes zoster" at another hospital, experiencing erythema, blisters, and pain on the right side of his thigh and buttock. Erythema extended unilaterally across the right thigh anterior and lateral surface reaching the superolateral surface or right buttock, forming fused bands with clusters of blisters. The lesions healed with hyperpigmented lesions after 3 weeks of therapy as per the patient (records not available). Three months from the time of presentation, keloid-like lesions emerged, evolving into prominent, expanding scars displaying classic keloid features [Figure 1]. The patient tried application of coconut oil and some home remedies with no relief as the keloids extended beyond the initial site, causing localized itching and pain. The patient had no prior keloid or family history and was HIV negative.Figure 1: Keloid scar present on the anterior (a) and posterior (b) surface of right thigh at the site of previous herpes zosterThis is referred to as "Wolf's isotopic response" which refers to the manifestation of a new, unrelated disease at a site where a previous ailment has healed. While numerous instances of this phenomenon are documented in the literature, the exact underlying mechanisms triggering this distinctive response remain unclear and continue to challenge our comprehension. Lesions of diseases such as psoriasis,[3] lichen planus,[4] granuloma annulare,[5] and morphea[6] have also been reported in the literature, occurring postzoster infection. There have been case reports in the past on keloid formation postherpes zoster episode in the literature.[7-9] Later to the herpetic episode, keloid formation is a rare complication which can be associated with PHN also, as in this case. Oral antivirals administered during the episode probably would have prevented PHN to some extent, but this was made worse in our patient by the pain and itching of keloids. These lesions can also bring along a therapeutic challenge as keloids are difficult to treat and usually require a long-term therapy.[1] Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.