Abstract

To the Editor: Pruritus ani (PA) is an unpleasant sensation of itching and an urge to scratch the skin around the anal orifice. It is very common and a socially embarrassing condition which is often poorly managed. PA is classified as idiopathic when there is an absence of any apparent anorectal or colonic etiology, and secondary when PA is attributable to an identifiable etiology. The causes of secondary PA are numerous and include anorectal diseases such as fissures, proctitis, fistula, hemorrhoids, abscess, and malignant conditions such as rectal cancers and adenomatous polyps that can present initially with PA. A number of dermatologic skin lesions such as lichen planus, psoriasis, eczema, lichen sclerosis et atrophicus, and seborrhea are associated with PA. Infectious causes include Candida albicans, dermatophytes,Staphylococcus aureus, Corynebacterium minutissimum (erythrasma), group A β-hemolytic Streptococcus, human Papillomavirus, herpes simplex, Enterobius vermicularis, and Sarcoptes scabiei. A number of medications have been reported to cause PA. They include colchicines, quinidine, mineral oil, and neomycin. Systemic disease such as diabetes mellitus and lymphoma can cause this annoying problem. Idiopathic PA is related to consumption of foods such as tomatoes, citrus fruits, nuts, chocolate, coffee, tea, cola, and beer. Irritants such as fecal soiling, excess moisture, soap, aggressive anal wiping, and scented toilet paper aggravate PA. Commonly, poor anal hygiene can be a setup for itching. The causes of PA may be difficult to determine, thus making it a potentially difficult condition to treat. It has also been suggested that psychological factors may play a role in the genesis of anal itching. ¹ Though there is no difference in fecal microflora in patients with PA, it is thought that bacterial endopeptidases, exotoxins, and intestinal lysozymes act as irritating agents. ² If the patient scratches, causing breaks in the sensitive perianal skin, these substances might penetrate into the dermis resulting in inflammation and release of irritating compounds. A vicious cycle of severe itching and scratching ensue. Many patients worsen the injury by cleaning the area with soaps and vigorous rubbing, or by applying topical medications that further irritate the skin. When PA does not respond to conservative therapy and when symptoms have existed for a long time, a high index of suspicion for the presence of malignancy should be maintained. ³ The management of PA is directed toward the underlying cause. It is estimated that 25 to 75% of patients with PA have an associated disorder. ⁴ A favorable response to specific medical therapy is seen in dermatologic conditions such as psoriasis, eczema, and mycotic dermatitis. Surgery also improves PA secondary to anorectal disorders such as fissures, extramammary Paget disease, fistulas, and abscesses.