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Vol. 30, No. 6, 2018 739 Received September 8, 2017, Accepted for publication January 5, 2018 Corresponding author: Alice He, Department of Dermatology, Johns Hopkins University School of Medicine, Cancer Research Building II, 1550 Orleans Street, Baltimore, MD 21231, USA. Tel: 410-955-5933, Fax: 410-955-8645, E-mail: [email protected] ORCID: https://orcid.org/0000-0002-1938-0619 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/ licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Copyright © The Korean Dermatological Association and The Korean Society for Investigative Dermatology dermal cysts after the presentation of herpes zoster which had occurred 1 year prior. Various hypotheses about the pathogenesis of the epidermal cyst and milia exist. Physical damage and histological inflammation of the skin by herpes zoster and bullous disorders may induce the epidermal cyst and milia. In particular, the use of immunosuppressive drugs may contribute to the development of a cyst more easily by exacerbating the inflammation imbalance and pilosebaceous unit occlusion. Our case is the second case of an epidermal cyst caused by Wolf’s post-herpetic isotopic response, but it is the first case that occurred during a short period in a healthy adult without using of immunosuppressive agents. The incidence of herpes zoster is increasing every year with an increased lifespan and the use of various immunosuppressive agents. Considering these tendencies, it is also assumed that the isotopic response caused by the herpes zoster would also increase. Based on this case, physicians should keep in mind that multiple epidermal cysts could occur from Wolf’s post-herpetic isotopic response in healthy adults. CONFLICTS OF INTEREST