Pruritus ani (also known as anusitis) is the irritation of the skin at the exit of the rectum, known as the anus, causing the desire to scratch. The intensity of anal itching increases from moisture, pressure, and rubbing caused by clothing and sitting.
Pruritis ani is a common medical problem affecting both men and women. This information was composed to help patients understand pruritis ani, its symptoms, evaluation, and treatment options. This information may also be helpful to individuals or caregivers of patients who are suffering from pruritis ani. Pruritis ani most commonly affects adults, affecting from 1% to 5% of people in the general population. Men are more commonly affected than women with a 4:1 ratio. The condition is most common in people age 40s to 60s. There are many causes of pruritis ani, and an accurate diagnosis is important in order to treat the specific cause. Medical management of pruritis ani often provides patients with relief of their symptoms and improves their quality of life.
Pruritis ani is a Latin term meaning “itchy anus” and is defined as an unpleasant sensation of the skin around the anus (i.e., rectal opening) that produces the desire to scratch. Pruritis ani is classified as primary or secondary. The primary form is the classic syndrome which may not have an identifiable cause (referred to as “idiopathic”) and the secondary form has an identifiable, and often specifically treatable, cause.
Minimal stimulation of the skin may cause itching. The subsequent scratching may cause injury to the skin which produces a larger area of irritated skin. Continued scratching causes the need to scratch more, making the problem worse.
This symptom of pruritis or itching is common to many anorectal conditions. One must consider hemorrhoids, excessive skin tags, fecal soilage or incontinence, anal fistulae (abnormal passageways between the bowel and an organ or skin surface), anal fissures (painful clefts or grooves) and anal warts as possible causative agents. It is not always understood what causes the long-standing history of primary pruritis ani. It is believed that an irritating secretion from the anal canal may cause the itching. The local nerve fibers in the skin may become chronically active with repetitive trauma or scratching for prolonged periods of time. There can also be itching related to disorders of nerve pathways or itching related to a central nervous system stimulus such as medications. Occasionally, itching may also be psychogenic (symptoms arise from the mind, as opposed to another organ).