Pruritus Ani: the neglected stepchild of coloproctology

Pruritus ani (PA) is a chronic unpleasant itching and/or burning sensation in the perianal region that affects up to 5% of the population. It can be secondary or idiopathic, and it can dramatically affect the quality of life of the patient. A substantial number of patients do not respond adequately to the majority of treatments available and the pathophysiology of PA has not yet been completely elucidated. A multidisciplinary approach aimed at detecting and addressing any possible causes is paramount in secondary PA. In chronic indeterminate PA in patients more than 50 years of age, a colonoscopy may be indicated to rule out a tumour. In mild-moderate idiopathic PA, self-care measures, including administration of a short cycle of a topical steroid and an attempt to exclude causative items from the diet with the goal of breaking the vicious cycle (itching-scratching-itching), may be effective. In cases of severe unresponsiveness PA, intradermal injection of methylene blue in the perianal area represents a reasonable option with a high rate of success in the short term and with an acceptable number of complications. Unfortunately, no international guidelines or consensus conference exists, and most of the literature available on this topic is anecdotal or based on small case series or on a few small randomized trials. Società Italiana di Chirurgia Colo Rettale www.siccr.org 2017; 45: 383-395 www.siccr.org 384 INTRODUCTION Pruritus ani (PA) is a relatively common condition characterized by a chronic unpleasant itching and/or burning sensation in the perianal region. It can affect up to 5% of the population and has a 4:1 male predominance. PA most commonly presents between 40 and 60 years of age and can result in significant discomfort and a worse quality of life for the patient. Because most individuals do not consult a doctor and large population-based studies are rare, the true prevalence of PA is probably underreported and the disorder is likely undertreated. In a recent survey of general practitioners in France. regarding the prevalence of proctological symptoms in their patients, PA was the third most common symptom reported (22%) after bleeding and pain. PA can be either secondary or idiopathic (primary). Idiopathic PA accounts for 25% to 90% of cases and often represents a clinical challenge due to the lack of a long-lasting effective therapy along with a high rate of recurrence after seemingly successful treatment. Our understanding of the pathological features and management of the disorder is based on case reports/case series, a few randomized trials on a small number of patients and some excellent reviews that have attempted to unify the literature. Currently, no international guidelines or multidisciplinary consensus conferences are available. For these reasons, PA has been defined as “the least researched everyday symptom from which humans suffer” [2] or as a “condition that eludes all attempts at cure” . More than 100 causes of PA have been reported in the literature. In 1966, Caplan [4] reported that perianal skin is more prone to develop itching than other body areas. Different factors (such as soiling, inflammation, and infection) may stimulate below the pain threshold specific superficial unmyelinated C-fibres in the perianal area, producing an itching sensation. The feedback from scratching can cause excoriation and inflammation leading to a vicious cycle. Recognizing and avoiding all irritating factors, along with breaking this cycle, is the key to successful treatment.