Immunocompromised cutaneous district, isotopic, and isopathic phenomena-Systematic review

Although the development of lesions in skin areas that have undergone injury has long been known, understanding of its pathogenesis is limited. Depending on their peculiarities, those events have been described as isomorphic, reverse isomorphic, pseudoisomorphic, isotopic, and isopathic phenomena. Ruocco's immunocompromised cutaneous district (ICD) concept was proposed to include all those phenomena.

We performed a systematic review and critically evaluated the current understanding about ICD and its relationship with the isotopic and isopathic phenomena.

To illustrate the complexity of the theme, we present a case of subclinical leprosy, whose manifestation was brisk in an old tattoo. The possible interaction between the approached phenomena, acting in the genesis of the disease, made this a pertinent study. The research was conducted under the PRISMA-P guidelines, in seven biomedical databases between 1996 and 2018. The eligibility criteria were systematic reviews, meta-analyses, clinical studies, and case series, written in English, French, Italian, Portuguese, or Spanish.

Using standardized keywords, 1220 articles were identified. After applying the eligibility criteria, 53 studies were selected.

This review ratifies that all these phenomena are aspects of one single condition. They can be integrated into the ICD concept with the pathogenesis including: (a) neural damage (peripheral or central) and (b) chronic lymphedema. Both may change the local neuroimmune interaction. The identification of these phenomena and the understanding of their pathogenesis are of paramount importance, to define the diagnosis and choose the therapeutic strategy.