> Table of Contents > Pruritus Ani
Pruritus Ani
Jessica Davis, MD
Pia Prakash, MD
Marie L. Borum, MD, EdD, MPH
image BASICS
DESCRIPTION
  • Intense, unpleasant anal and perianal itching and/or burning
  • Usually acute
  • Can be classified as idiopathic (primary) pruritus ani (50-90%) or secondary to anorectal pathology (1)
EPIDEMIOLOGY
Incidence
  • 1-5% of the general population (1)
  • Predominant age: 30 to 60 years (1)
  • Predominant sex: male > female (4:1) (1)
Prevalence
Difficult to estimate as often unreported, one study found present in 2.4% of patients visiting PCPs (2).
ETIOLOGY AND PATHOPHYSIOLOGY
  • Perianal itching (primary or secondary) incites itch-scratch cycle that may self-perpetuate, as resulting lichenification worsens pruritus.
  • Etiologies of primary pruritus ani
    • Poor anal hygiene
    • Loose or leaking stool that makes hygiene difficult—of note, interestingly, patients with abdominal ostomy bags typically do not complain of pruritus (1).
    • Internal sphincter laxity
    • Idiopathic
  • Etiologies of secondary pruritus ani
    • Inflammatory dermatologic disorders
      • Allergic contact dermatitis (soaps, perfumes, or dyes in toilet paper, topical anesthetics, oral antibiotics)
      • Psoriasis: Lesions tend to be poorly demarcated, pale, and nonscaling.
      • Atopic dermatitis ± lichen simplex chronicus: Patients are likely to have asthma and/or eczema.
      • Eczema from dietary elements (citrus, vitamin C supplements, milk products, coffee, tea, cola, chocolate, beer, wine)
      • Seborrheic dermatitis
      • Lichen planus: may be seen in patients with ulcerative colitis and myasthenia gravis
    • Colorectal and anal pathology: rectal prolapse, hemorrhoids, fissures or fistulas, chronic diarrhea/constipation, papillomas, condyloma, polyps, cancer
    • Malignancies: uncommon, but pruritus ani may be presenting symptom of Bowen or Paget disease
    • Infectious etiologies: dermatophytes (Tinea), bacteria (Staphylococcus aureus, &bgr;-hemolytic Streptococcus, Corynebacterium minutissimum [Erythrasma], gonorrhea, syphilis), viruses (herpes simplex virus [HSV], human papillomavirus [HPV], molluscum), parasites (pinworms, rarely scabies, or pediculosis)
    • Mechanical factors: vigorous cleaning and scrubbing, tight-fitting clothes, synthetic undergarments
    • Systemic diseases: diabetes mellitus (most common), chronic liver disease, renal failure, leukemia or lymphoma, hyperthyroidism, anemia
    • Chemical irritants: chemotherapy, diarrhea (often from antibiotic use)
    • Psychogenic factors: anxiety-itch-anxiety cycle
RISK FACTORS
  • Obesity
  • Excess perianal hair growth, excessive perspiration
  • Underlying anorectal pathology
  • Underlying anxiety disorder
  • Caffeine intake has been correlated with symptoms.
GENERAL PREVENTION
  • Good perianal hygiene
  • Avoid mechanical irritation of skin (vigorous cleaning or rubbing, harsh soaps or perfumed products, excessive cleansing with dry toilet paper or “baby wipes,” scratching with fingernails, or tight/synthetic undergarments). Minimize moisture in perianal area (absorbent cotton in anal cleft may help keep area dry).
  • Avoid laxative use (loose stool is an irritant).
COMMONLY ASSOCIATED CONDITIONS
See earlier listing of conditions causing perianal irritation.
image DIAGNOSIS
PHYSICAL EXAM
  • Perianal inspection for erythema, hemorrhoids, anal fissures, maceration, lichenification, rashes, warts, excoriations, neoplasia
  • Digital rectal exam to check for masses and to evaluate internal sphincter tone, Valsalva to evaluate for prolapse
  • Anoscopy to evaluate for hemorrhoids, fissures, other internal lesions
  • Classification based on gross appearance
    • Stage 1: erythema, inflamed appearance
    • Stage 2: lichenification
    • Stage 3: lichenification, coarse skin, potential fissures or ulcerations (1)[C]
DIFFERENTIAL DIAGNOSIS
  • “ITCHeS” acronym (4)
    • Infection: pinworms, dermatophytes, grampositive bacteria, HSV, gonorrhea, chlamydia, syphilis, HPV, erythrasma, scabies
    • Topical irritant: detergents, garments, deodorants, perfumes, stool leakage
    • Cutaneous/cancer/colorectal: eczema, psoriasis, lichen planus, lichen sclerosus, seborrheic dermatosis, squamous cell cancer, extramammary Paget disease, Bowen disease, melanoma, fistula, fissure, prolapse, hemorrhoids, colorectal cancer
    • Hypersensitivity: foods (the “C's” above), medications (colchicine, quinidine, mineral oil)
    • eSystemic: diabetes, uremia, cholestasis, hematologic malignancy
DIAGNOSTIC TESTS & INTERPRETATION
Initial Tests (lab, imaging)
Depending on patient's history and exam, consider the following:
  • Pinworm tape test; stool for ova and parasites
  • CBC, comprehensive metabolic panel, A1c, thyroid studies to identify underlying systemic disease
  • Wood lamp examination will show coral-red fluorescence in erythrasma (1).
  • Skin scraping with potassium hydroxide (KOH) prep for dermatophytes or candidiasis (as etiology or as superinfection) and mineral oil prep for scabies
  • Perianal skin culture (bacterial superinfection)
  • Hemoccult testing of stool
Pediatric Considerations
Pinworms are common in children.
Follow-Up Tests & Special Considerations
Anal DNA polymerase chain reaction (PCR) probe for gonorrhea and chlamydia and anal Pap smear for HPV if receptive anal intercourse
Diagnostic Procedures/Other
  • Biopsy suspicious lesions (e.g., lichenification, ulcerated epithelium, refractory cases) to exclude neoplasia
  • Consider colonoscopy if history, exam, or testing suggests colorectal pathology (family history of colorectal disease, especially if age >40 years, weight loss, rectal bleeding, change in bowel habits).
Geriatric Considerations
  • Stool incontinence may be a predisposing factor.
  • Consider systemic disease.
  • Higher likelihood of colorectal pathology
image TREATMENT
GENERAL MEASURES
  • Educate patients regarding proper anal hygiene and avoidance of chemical and mechanical irritants (1).
  • High-fiber diet and/or bowel regimen to maintain regular bowel movements (1)
  • Avoid tight-fitting clothing and use cotton undergarments.
  • Talcum powder or cornstarch if excess moisture (1)
  • Wear cotton gloves at night to control nocturnal scratching (1).
MEDICATION
First Line
  • Treat underlying infections: fungal or dermatophyte infection with topical imidazoles, bacterial infection with topical antibacterials.
  • Break itch-scratch cycle with low-potency steroid cream such as hydrocortisone 1% ointment applied sparingly up to 4 times daily (1)[A]. Discontinue when itching subsides. Recommended not to use >12 weeks due to risk of skin atrophy.
  • If no response with low-potency steroid, consider high-potency steroid cream.
  • Antihistamines may be useful until local measures take effect, particularly sedating antihistamines, which will reduce nighttime itching.
  • P.869

  • Some experts suggest a trial of tricyclic antidepressants to reduce nighttime scratching.
  • Zinc oxide can be used after completing steroid course for barrier protection (3)[C]; petroleum jelly is another barrier treatment.
  • Although trial data are mixed, topical capsaicin cream may be used in combination with steroid cream if refractory itch or hypersensitized skin (1,5)[A].
  • A small RCT showed benefit with 0.1% tacrolimus ointment; this may be a good choice in patients with skin thinning at risk for atrophy from prolonged steroid use (6)[C].
  • Several small case series have shown symptomatic benefit with methylene blue injection; this may be an additional option for patients with refractory symptoms (7)[C].
Second Line
Radiation may be used to destroy nerve endings (create permanent anesthesia) in intractable cases. This is almost never indicated but is very effective.
ISSUES FOR REFERRAL
  • Intractable pruritus: Consider referral to gastroenterology (for colonoscopy) or dermatology (for additional treatment, possibly injections). Refractory or persistent symptoms should signal the possibility of underlying neoplasia, as pruritus ani of long duration is associated with a greater likelihood of colorectal pathology.
  • If risks or red flags for colon cancer are present, refer for colonoscopy.
SURGERY/OTHER PROCEDURES
None unless malignancy identified
image ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
See patient in 2 weeks if not improving. Check for persistent lichenification. With refractory pruritus or lichenification that does not resolve, consider underlying malignancy.
DIET
  • Trial elimination of foods and beverages known or suspected to exacerbate symptoms: coffee, tea, chocolate, beer, cola, vitamin C tablets in excessive doses, citrus fruits, tomatoes, or spices
  • Eliminate foods or drugs contributing to loose bowel movements. Add fiber supplementation to bulk stools and prevent fecal leakage in patients who have fecal incontinence or partially formed stools.
PATIENT EDUCATION
  • Review proper anal hygiene:
    • Resist overuse of soap and rubbing.
    • Avoid toiletry products with irritating perfumes and dyes.
    • Avoid use of ointments to the area, including witch hazel.
    • Wear loose, light cotton clothing.
    • If moisture is a problem, unmedicated talcum powder or cornstarch to keep the area dry.
    • Cleanse perianal area after bowel movements with water-moistened cotton.
    • Dry area after bathing by patting with a soft towel or by using a hair dryer (1).
  • Avoid medications that cause diarrhea or constipation.
  • Avoid foods implicated in pruritus ani: caffeine, cola, chocolate, citrus, tomatoes, tea, beer/wine (3)[C].
  • Use barrier protection if engaging in anal intercourse.
  • If unable to completely empty rectum with defecation, use small plain-water enema (infant bulb syringe) after each bowel movement to prevent soiling and irritation.
PROGNOSIS
  • Conservative treatment is successful in ˜90% of patients.
  • Idiopathic pruritus ani often is chronic, waxing and waning. Regardless of etiology, however, pruritus ani may be persistent and recurrent.
REFERENCES
1. Markell KW, Billingham RP. Pruritus ani: etiology and management. Surg Clin North Am. 2010;90(1): 125-135.
2. Abramowitz L, Benabderrahmane M, Pospait D, et al. The prevalence of proctological symptoms amongst patients who see general practitioners in France. Eur J Gen Pract. 2014:20(4):301-306.
3. Nasseri YY, Osborne MC. Pruritus ani: diagnosis and treatment. Gastroenterol Clin North Am. 2013;42(4):801-813.
4. Henderson PK, Cash BD. Common anorectal conditions: evaluation and treatment. Curr Gastroenterol Rep. 2014:16(10):408.
5. Gooding SM, Canter PH, Coelho HF, et al. Systematic review of topical capsaicin in the treatment of pruritus. Int J Dermatol. 2010;49(8):858-865.
6. Suys E. Randomized study of topical tacrolimus ointment as possible treatment for resistant idiopathic pruritus ani. J Am Acad Dermatol. 2012;66(2): 327-328.
7. Samalavicius NE, Poskus T, Gupta RK, et al. Long-term results of single intradermal 1% methylene blue injection for intractable idiopathic pruritus ani: a prospective study. Tech Coloproctol. 2012;16(4):295-299.
Additional Reading
&NA;
  • Al-Ghnaniem R, Short K, Pullen A, et al. 1% Hydrocortisone ointment is an effective treatment of pruritus ani: a pilot randomized controlled crossover trial. Int J Colorectal Dis. 2007;22(12):1463-1467.
  • Handa Y, Watanabe O, Adachi A, et al. Squamous cell carcinoma of the anal margin with pruritus ani of long duration. Dermatol Surg. 2003;29(1):108-110.
  • Lacy BE, Weiser K. Common anorectal disorders: diagnosis and treatment. Curr Gastroenterol Rep. 2009:11(5):413-419.
  • Lysy J, Sistiery-Ittah M, Israelit Y, et al. Topical capsaicin—a novel and effective treatment for idiopathic intractable pruritus ani: a randomised, placebo controlled, crossover study. Gut. 2003;52(9):1323-1326.
  • Rucklidge JJ, Saunders D. Hypnosis in a case of long-standing idiopathic itch. Psychosom Med. 1999;61(3):355-358.
  • Schubert MC, Sridhar S, Schade RR, et al. What every gastroenterologist needs to know about common anorectal disorders. World J Gastroenterol. 2009;15(26):3201-3209.
  • Siddiqi S, Vijay V, Ward M, et al. Pruritus ani. Ann R Coll Surg Engl. 2008;90(6):457-463.
  • Ucak H, Demir B, Cicek D, et al. Efficacy of topical tacrolimus for the treatment of persistent pruritus ani in patients with atopic dermatitis. J Dermatolog Treat. 2013;24(6):454-457.
  • Weichert GE. An approach to the treatment of anogenital pruritus. Dermatol Ther. 2004;17(1):129-133.
  • Zuccati G, Lotti T, Mastrolorenzo A, et al. Pruritus ani. Dermatol Ther. 2005;18(4):355-362.
See Also
&NA;
Pinworms; Pruritus Vulvae
Codes
&NA;
ICD10
L29.0 Pruritus ani
Clinical Pearls
&NA;
  • Pruritus ani is characterized by intense anal and perianal itching and/or burning.
  • Usually idiopathic or related to skin irritation with subsequent scratch-itch-scratch cyle
  • Conservative treatment with good perianal hygiene and reassurance are successful in 90% of patients.
  • Consider trial of dietary elimination of “C's”—citrus, vitamin C supplements, calcium, caffeine, coffee, cola, chocolate.
  • Rule out infection in immunosuppressed patients.
  • Consider underlying malignancy if refractory