Pruritus ani

What is Pruritus ani? Pruritus ani is an unpleasant sensation that provokes an intolerable desire to scratch the skin around the anal area. It has been recognised since antiquity and seems to affect 1% to 5% of the population. It is a latin term meaning itchy anus. It is called “idiopathic pruritus ani” when no clear cause is found. Contributing factors are found in up to 75% of cases including anorectal skin conditions and infections.

What causes pruritus ani? The perianal skin is oily, mildly acidic and naturally protecting. Irritants may be mechanical, thermal, chemical, or electrical. If these irritate pain related nerve endings (pain receptors – nociceptors) they cause pain, and if they irritate itch-related nerve endings (itch sensors – pruriceptors), they cause itch. Itch sensors in the upper layer of skin around the anus are often activated more at night and after a bowel movement and by heat, wool, moisture, leaking, soiling, stress, and anxiety. Subsequent scratching causes skin damage and “activation” of itch sensors – which may then increase in number or their sensitivity. Skin damage is first microscopic, then it may become inflamed and later it may thicken and ulcerate. Some patients have transient anal sphincter relaxation (worsened by things like coffee) which can lead to silent faecal soiling with leakage of further irritants such as enzymes and bacteria. These trigger the “activated” itch sensors and set up a self-defeating cycle of itch-scratch-damage.

What can I expect from my doctor? The doctor may ask if you have had any previous or current skin, gynaecological or gastrointestinal problems and if you had a recent change in bowel habit. Think about whether there is any relationship to food, medications new or old, or anal hygiene practices.

What factors might be consider to be contributing to pruritus ani?

Perianal conditions
haemorrhoids and anal fissures; anal fistulas, abscesses, proctitis, rectal or anal cancer or polyps
Gynaecological conditions
vaginal discharge or menopause
Skin disorders
atopic/contact dermatitis, lichen sclerosis/planus, psoriasis, or sensitive skin, (dermatographism, seborrheic dermatitis,vitiligo, squamous cell carcinomas, Paget’s disease)
Infectious disease
bacteria (Strep) and fungus (dermatophytes rarely candida), HPV virus, pinworms
coffee (both caffeinated and decaffeinated), tea, cola, beer, Red bull, tomatoes, chocolate, citrus fruits, spices, milk and other dairy products, seeds and nuts (including popcorn)
Medications or chemicals
tetracycline, colchicine, quinidine, topical local anesthetics and antibiotics, neomycin, ointments with parabens, shampoo, lanolin, nickel, potassium dichromate, rubbers, perfumes, Balsam of Peru etc
Psychological factors
anxiety, agitation, and stress, obsessions and personal dissatisfaction
fecal incontinence (common), excessive humidity, soap, excess scrubbing of the anus, persistent frequent loose motions or constipation

How is pruritus ani treated? First treatment is based on making changes to diet, toileting, hygiene and skin care to break the itch-scratch cycle and restore healthy naturally protecting perianal skin. This involves returning to its usual intact, dry, clean, oily and mildly acidic state. Treating any of the above contributors is critical. Even when no clear cause is found, patients can still be managed successfully by avoiding irritants and scratching and with modifying hygiene practices and lifestyle. Decreasing perianal leakage or soiling is critical. Very often the aim is comfort not cure.

toptentips for pruritus ani

  1. Break the itch-scratch cycle. Cut the finger nails short and avoid scratching or rubbing anal area even while asleep. If you have night time itch or waken, gently clean the area with below measures and apply agreed ointment or creams and don’t scratch.
  2. Avoid excessive cleaning. Use water only (or soap substitutes) on anal area and skin. Avoid soaps, bath oils or other cleansers and shampoos on the skin. Use bland emollients, Dove sensitive or dilute white vinegar (1 tablespoon diluted in 240mL water).
  3. Avoid toilet paper particularly vigorous wiping. Vigorous wiping can lead to irritation with premature retraction of the anoderm trapping stool which may seep out later causing a cycle of irritation. Use baby wipes, cotton wool/squares or tissues dipped in warm water or dilute white vinegar (above) or bland emollients (eg Cetaphil). Use minimum twice a day or more frequent if incontinent. Choose moist, non-perfumed baby wipes; however, for some it’s the solution and for others it’s the cause. Bidets are not common in Australia but a handheld shower head may be useful or showering after bowel motions (cold works for some, warm for others). Pat area dry or use cool setting hairdryer (avoid wash cloths).
  4. Take short showers (<15 mins) rather than baths. If bathing consider adding baking soda to the water (rather than soap/bath oil) or take a warm 5 minute Sitz baths three times a day
  5. Wear loose, cotton underwear. Avoid nylon and other synthetics. Wash in fragrance free soaps or detergents and avoid fabric softeners. If there’s excess moisture (often worse if hirsute or overweight), use a bit (¼) of a cotton ball, panty-liner or sanitary pad against the anus/in between buttocks against anus by day and night.
  6. Maintain a soft, well-formed non-irritating stool with the 3 F’s
    • a high fibre diet (30 grams per day) eg two servings of fruits and / or vegetables with each meal. If it is difficult, at the same time every day, use a fiber supplement such as LSA (linseed, sunflower, almond), Normafibe, Psyllium/ Metamucil, One bowl of All-Bran™ each morning, Benefiber® as directed on the bottle.
    • Increase your fluid intake by drinking 8 glasses (8 x 125mL) of non-caffeinated, non-alcoholic drinks/day eg. two glasses with each meal. Increase fluid intake on hot days.
    • Exercise and try to use the correct sitting position with you feet up on a stool
  7. Trial excluding high risk foods and medications if these seem related. These may change the skin acidity, cause irritation or lower anal sphincter tone. These include caffeine (Coffee or cola, caffeinated soda, energy drinks like Red Bull and decaf), chocolate or chocolate containing foods; citrus (example: oranges, orange juice, lemons), grapes, tomatoes or tomato sauces, spicy foods, beer, ale and alcoholic beverages, seeds, popcorn and nuts, milk and other dairy. Exclude above food and drinks for 2 weeks then slowly reintroduce. Some find a threshold effect ie. 2 cans of beer, cups of tea or coffee may be okay but 3 causes itch. For others a high fibre diet causes excess flatulence which leads to soiling of perianal skin and irritation. So decrease in fibre may be needed for some.
  8. Short trials 1-2 weeks of soothing ointments or creams. Apply 3-6 times a day, after showers & after opening bowels. Agents included zinc oxide (eg AnuSol or Rectinol particularly if there is faecal soiling), acid mantle cream, emollient, petroleum jelly (Vaseline, mixed bees wax and olive oil, Vicks), dry corn starch, lanoline, a green tea bag, aloe vera. You may also trial a thin layer of hydrocortisone 1% never longer than a 1 week. Some use sedating antihistamines if sleep disturbance is a problem
  9. Take care with all medications and ointments. Use of anything on the skin around the anus including ointments and creams can be challenging. Try to avoid all OTC (over the counter) ointments and creams including scented products unless directed, in case you have a hidden allergy. Almost all have been show to help some and worsen others. Pruritus ani has been caused by steroids (hydrocortisone), lanoline, oils, parabens, neomycin, local anaesthetics and even some wet/baby wipes. Stopping steroid ointments can lead to rebound itch and dependence on steroids or “steroid addiction.” If rebound itch occurs try to wean steroid using it every second day or once or twice a week. Stop all non-essential medications and consider a 2-6 week “drug holiday” of any prescription under close medical supervision. If you are using a medicated cream or wipes and itching gets worse, stop using the cream immediately.
  10. If these conservative measure don’t work after 4-6 weeks, your doctor may arrange a dermatologist consultation to help identify a skin condition, patch testing or, under close medical supervision, the following can be tried: local measures such as topical steroid (hydrocortisone, desonide or Resolve plus 1 cream), cotrimazole or Xyloproct,  topical pepper cream 0.006% capsaicin ointment. Tacrolimus ointment (0.03-0.1%) or  intradermal injection of 0.5-1.0% methylene blue mixed with lignocaine and a steroid has been successful in difficult cases. Antihistamines (H1 and 2 blockers; sedating at night), low dose tricyclics antidepressants (doxepin, nortriptyline, amitriptyline) and anticonvulsants (gabapentin). If seepage continues despite fibre careful use of loperamide and cholestyramine can help to firm loose stools.