A Review of the Therapeutic Interventions

Background: Pruritus Ani (PA) is the chronic itch of perianal skin and is poorly understood. There is a knowledge gap in understanding the pathophysiology and management of PA as there has been little research. The literature is sparse and of variable quality. There have been recent studies in understanding pruritic processing. We have performed a critical review of the literature concerning therapeutic inventions with the insights gained from this new understanding. In addition, an overview of PA is presented. Method: A systematic review in accordance with Preferred Reporting Items for Systematic reviews and Meta-analysis (PRISMA) guidelines was undertaken. With the heterogeneity of the reviewed studies it was not possible to perform a true systematic review, but a critical appraisal has been performed using the same methodology. Results: There are five randomised trials, one controlled study, one observational study, and eight case series critically appraised. The studies concerning topical and injectable intradermal steroid, topical tacrolimus and topical capsaicin have not provided evidence for their therapeutic benefit. Studies suggest methylene blue anal tattooing may beneficial in the treatment of PA. Conclusions: The aim of this paper was a review of the best evidence available on the current treatment of PA. We set up to perform a systematic review, but were unable to due to the heterogeneity of evidence; hence a critical review was performed. There remains an evidence gap in the pathophysiology and treatment of PA. More research is needed, but there are so many unknowns about the nature of PA, this will be currently difficult to perform. The understanding of pruritus and pruritic processing is in its infancy. Newer therapies such as tacrolimus and capsaicin have failed to live up to initial promise, although they can be effective in a few. Anal tattooing shows the greatest promise. *Corresponding author: Ms. Arifa Siddika, RegistrarColorectal surgery, Broomfield Hospital, Mid Essex NHS Trust, Chelmsford, Essex, CM1 7ET, UK; E-mail: [email protected] Citation: Arifa Siddika. A Review of the Therapeutic Interventions in the Management of Pruritus Ani. (2017) Invest Dermatol Venerol Res 3(1): 91102. A Review of the Therapeutic Interventions in the Management of Pruritus Ani Arifa Siddika*, Shahab Siddiqi Received date: November 14, 2016 Accepted date: January 4, 2017 Published date: January 10, 2017 DOI: 10.15436/2381-0858.17.1220 Invest Dermatol Venereol Res | Volume 3: Issue 1 Siddika, A., et al. symptoms that have a significant impact on quality of life. PA is one of those symptoms that can be managed by a variety of clinicians, mostly general practitioners, dermatologists and colorectal surgeons. Unfortunately, like irritable bowel syndrome and chronic pain syndromes, there is an underestimation of how significantly PA can affect quality of life. In addition, due to a scientific knowledge gap, many clinicians are not empathetic towards this patient group. At worst, some clinicians consider that patients are in some way to blame for their condition, especially when available therapies have not been successful. PA has historically been considered a symptom rather than a diagnosis, but the understanding of pruritic processing has developed recently and may challenge this. The limited evidence base has led to multiple theories about how perianal itch was the end result of multiple seemingly unrelated triggers. This evidence base must be interpreted critically. In a recent landmark psychology paper[3], publication bias was shown to have an even greater impact than previously thought. In this work, 100 studies were reproduced, following the methods used in the original studies as closely as possible. Ninety-five of the original studies, but only a third of the replication studies were reported to have statistically significant results. Even when the data from the original and replication studies were combined, only two thirds yielded statistically significant results. Clinical studies in other fields are probably affected by reproducibility and publication bias to a similar extent. In a field of research as small as PA, publication bias and reproducibility may be even more of a problem, and all published data should be viewed critically. The aim of this review was to present an overview of PA and its management, to critically appraise the evidence base for therapeutic interventions used in the management of PA. We have also presented the current understanding of pruritic processing and its neuronal pathways, as these have changed considerably and have a bearing on the analysis of the available research. Methodology A systematic review in accordance with Preferred Reporting Items for Systematic reviews and Meta-analysis (PRISMA) guidelines was undertaken[4]. A search of indexed citations from MEDLINE, Cochrane library and PUBMED databases was undertaken using the following terms; “Pruritus Ani”, “anal itching”, “anal irritation”, “pruritus AND (anal or anus or ani or ano)”, “itch* AND (anal or anus)” in October 2015. In addition, a “related articles” search, forward citation functions was performed and the references of published articles reviewed. All abstracts were reviewed and the full texts of all potentially relevant papers were considered. Only peer-reviewed publications in the English language were included in the review. Study quality was assessed according to the recommendations of the strengthening the reporting of observational studies in epidemiology (STROBE) statement[5]. Author and year of publication, number of patients within the study, method and treatments of pruritus ani were extracted from each article included in the review. Literature searches have found only 283 publications involving PA over a 90-year period, with the majority being abstracts, review articles or opinions. Due to heterogeneity of the evidence identified it has not been possible to carry out a formal systematic review (Figure 1). However, the same methodology has been used to produce a critical review of literature on management of PA. www.ommegaonline.org Pruritus Ani Invest Dermatol Venereol Res | Volume 3: Issue 1 92 General processing of pruritus Itch processing is highly complex, but is not fully understood. There are four subtypes of itch, i.e., pruriceptive, neurogenic, neuropathic and psychogenic[6]. Pruriceptive itch is the classical itch caused by dermal sensation and injury, chemical stimulation, dry skin, dermatological conditions, infestations, and histamine release. Neurogenic itch is caused by systemic conditions such as liver disease and renal failure where there is direct activation of higher centres of itch with no abnormality of itch processing. Neuropathic itch results from the pathological activation of itch processing in certain neurological disorders such as peripheral neuropathy, post-herpetic neuralgia, nerve compression and multiple sclerosis. Psychogenic itch may occur with some psychological conditions that involve primary