Derived from Latin, pruritus ani refers to perianal and anal itching. Itching is a sensation that causes an impulsion to scratch. Primarily mediated by histamine, itch results from irritation of the unmyelinated C fi bers that end in the dermal-epidermal junction [ 1 ]. The incidence of pruritus ani ranges from 1 to 5 % [ 2 , 3 ]. In a popula- tion study in Joliet, Illinois, of 102 randomly selected participants, 6 % reported anal itching in the past year [ 4 ]. In contrast, Keighley and Williams reported a 45 % incidence of pruritus ani within the past 5 years when surveying patients without gastrointestinal complaints seen in a hospital outpatient department [ 5 , 6 ]. Due to the embarrassing nature of the complaint, the incidence may be greater than stated. Males suffer from pruritus ani more frequently than females, with a ratio of 2:1 to 4:1 [ 2 , 7 , 8 ]. Although the symptom may arise at any age, it is most common in the 40s to 60s [ 2 ]. In the series of 200 patients with pruritus ani from Bowyer and McColl, the majority of their patients presented in their middle 40s, with a range of 12–76 years old [ 7 ]. Perianal itching usually is a transient, self-limited symptom, resolving without any medical intervention. However, in a subset of patients, pruri­tus ani may be chronic, even becoming debilitating. Bowyer and McColl reported that 40 % of their patients had experienced perianal itching for 5 years or longer [ 7 ]. Five patients (7 %) in the series from Smith and colleagues experienced pruritus ani for more than 30 years [ 9 ].