Pruritis ani (Guidelines)

Pruritus ani is generally a diagnosis made after exclusion of several important alternative diagnoses as shown in the flow chart below. Therefore, the history is crucial and some key points on the possible differentials are highlighted below. The treatment options are quite limited, hence the importance of identifying any possible causes that can be eliminated.

• Diet induced diet-induced pruritus is symmetrical, whereas infectious causes lead to an asymmetrical pattern of anal irritation. Avoiding food items known to aggravate pruritus ani these may include coffee, chocolate, citrus fruits, cola drinks, and dairy products. Caffeine is most commonly associated with pruritus. Consider a patient-led symptom diary to record relation to diet.
• Minor faecal incontinence of stool or leakage of mucus secondary to haemorrhoids or rectal prolapse can cause perianal itching and is a common cause of symptoms.
• Perianal infections by fungi (candida), parasites (eg threadworms, pinworms) and sexually transmitted infections can also result in pruritus.
• Primary dermatological conditions such as psoriasis, eczema can affect the perianal to cause itching.

Self-care measures are listed below and patients can also be signposted to the British Association of Dermatologists for information (see resources).

• Gently wash the perianal area with plain water after every bowel movement and at bedtime.
• Gently dry the perianal area by patting with a soft towel or cotton swabs, not by rubbing. A hair dryer on the cool setting can also be used.
• Avoid excessive rubbing or wiping with alcohol-based disinfectants or wet wipes.
• Wear loose cotton underwear, avoid tight clothing, and use stockings (instead of tights), to reduce sweating or excess moisture.
• Avoid talcum powder, soaps, perfumed products, or deodorant around the perianal area.
• Keep the perianal area cool at night (for example by using a light duvet or bed sheet).
• Avoiding foods and drinks known to aggravate pruritus ani these may include coffee, chocolate, citrus fruits, cola drinks, and dairy products. See resources: NICE CKS.
• Consider a patient-led symptom diary to record relation to diet.
• Avoiding scratching, if possible. Nails should be kept short, and cotton gloves worn at night, to reduce skin trauma
• If the patient is faecally incontinent, please consider referral to pelvic health physiotherapy, see resources: Faecal incontinence. 

Ensure regular and formed stools passed by titrating fibre and fluid intake, if necessary, bulk forming laxatives such as macrogols can be prescribed.

• For excoriated skin, consider a soothing preparation (containing ZnO) or the use of Vaseline as a barrier prior to bowel motions
• If perianal skin is inflamed a mild potent corticosteroid for a max 7 days can be trialled
• If no resolution in 6-8weeks refer to colorectal team for exclusion of lower GI cause
• Refractory pruritus can be difficult to treat and the management should be guided by secondary care.

There is strong evidence (level 1B) that titrating dietary fibre and fluid intake to pass regular, soft but formed stool significantly reduced PR bleeding. If necessary, bulk forming laxatives can be prescribed to achieve this. Regular formed motions will also help with seepage and faecal incontinence. Ideally, patients should aim for a Type 4 stool on the Bristol Stool Chart (see resouces). 

• For excoriated skin, treat as per Wound Formulary guidance (see resources).
• If perianal skin is inflamed a mild topical corticosteroid for a max 7 days can be considered but this would be at prescriber discretion. 
• If no resolution in 6 to 8weeks, refer to colorectal team for exclusion of lower GI cause.
• Refractory pruritus can be difficult to treat and the management should be guided by secondary care.