BASICSSonia Taneja, MD • Marie L. Borum, MD, EdD, MPH
BASICS
DESCRIPTION
• Intense, unpleasant anal/perianal itching and/or burning
• Usually acute
• Can be classified as idiopathic (primary) pruritus ani (~75% of cases) or secondary to anorectal pathology (1)
EPIDEMIOLOGY
Incidence
• Uncommon, 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
• Pruritus ani may be considered idiopathic (primary) or secondary to anorectal pathology with over 100 etiologies categorized by cutaneous, neuropathic, neurogenic, and psychogenic causes (3,4).
• Pruritus may create an irresistible desire to scratch the perianal area leading to a self-perpetuating itch-scratch-itch cycle.
• Consider primary pruritus ani when no other demonstrable causes can be found. This includes:
– Poor anal hygiene
– Loose or leaking stool that makes hygiene difficult. Patients with abdominal ostomy bags typically do not complain of pruritus (1).
– Internal sphincter laxity
• Etiologies of secondary pruritus ani:
– Inflammatory dermatologic diseases:
Allergic contact dermatitis (soaps, perfumes, or dyes in toilet paper, topical anesthetics, oral antibiotics)
Atopic dermatitis ± lichen simplex chronicus (patients also have asthma and/or eczema)
Psoriasis (lesions tend to be poorly demarcated, pale, and nonscaling)
Seborrheic dermatitis
Lichen planus (may be seen in patients with ulcerative colitis and myasthenia gravis)
Radiation dermatitis (3)
– Colorectal/anorectal diseases: rectal prolapse, hemorrhoids, fissures or fistulas, chronic diarrhea/constipation, polyps
– Infectious etiologies, may be sexually transmitted: bacteria (gonorrhea, chlamydia, syphilis), viruses (herpes simplex virus [HSV], condyloma acuminate from human papillomavirus [HPV], molluscum), parasites (pinworms, lice, scabies, or bed bugs), fungal (Candida, or dermatophytes like Tinea). Other bacteria (Staphylococcus aureus, β-hemolytic Streptococcus, Corynebacterium minutissimum [Erythrasma]) (3)
– Malignancies: melanoma, basal cell/squamous cell carcinoma, colorectal cancer, or (uncommon) the presenting symptom of Bowen or Paget disease
– 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)
– Dietary elements (citrus, milk products, coffee, tea, cola, chocolate, beer, wine, tomatoes, nuts)
– Psychogenic factors: anxiety–itch–anxiety cycle
RISK FACTORS
• Obesity
• Excess perianal hair growth, and/or 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 with dry toilet paper or baby wipes, harsh soaps or perfumed products, excessive scratching with fingernails, or wearing 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).
DIAGNOSIS
HISTORY
• Patient presents with complaint of anal and/or perianal itching, burning, or excoriations present.
• Inquire about:
– Timing (when it started, when it is worse)
– Frequency of cleansing and products used on affected area
– Change in bowel habits
– Melena or hematochezia
– Recent antibiotic use
– Skin disorders (psoriasis, eczema)
– Rectal or vaginal discharge, menstrual cycle
– Dietary history: Focus on the “C”s: caffeine, coffee, cola, chocolate, citrus, calcium (dairy) (3).
– Medical history (hepatitis, iron deficiency anemia, and diabetes in particular)
– Family history of colorectal cancer
– Anal receptive intercourse
– Change in toiletry products
– Household members (particularly children) with itching (possible pinworms)
– Clothing preference (tight, synthetic) (1)
PHYSICAL EXAM
• Perianal visual inspection for erythema, hemorrhoids, anal fissures, maceration, lichenification, warts, polyps, excoriations, neoplasia, stool seepage
• Classification based on gross appearance
– Stage 1: erythema, inflamed appearance
– Stage 2: lichenification
– Stage 3: lichenification, coarse skin, potential fissures or ulcerations (1)[C]
• Digital rectal exam to evaluate for masses, internal sphincter tone, pain. Valsalva to evaluate for prolapse
• Anoscopy to evaluate for hemorrhoids, fissures, other internal lesions
DIFFERENTIAL DIAGNOSIS
• “ITCHeS” acronym (4)
– Infection: Candida, parasites (scabies, pinworms), HPV, HSV, bacterial (gram-positive bacteria, gonorrhea, chlamydia, syphilis)
– Topical irritants: soaps/detergents, garments, deodorants, perfumes, stool leakage
– Cutaneous/Cancer/Colorectal: eczema, psoriasis, lichen planus, lichen sclerosus, seborrhea, skin cancer, extramammary Paget disease, Bowen disease, fistula, fissure, prolapse, hemorrhoids, colorectal cancer
– Hypersensitivity: foods (the “C’s” above), medications (colchicine, quinidine, mineral oil)
– eSystemic: diabetes, iron deficiency anemia, uremia, cholestasis, hematologic malignancy
DIAGNOSTIC TESTS & INTERPRETATION
Initial Tests (labs, imaging)
Depending on 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
Pinworms are common in children; consider perianal Crohn disease (5).
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; evaluate etiology.
• 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
TREATMENT
GENERAL MEASURES
• Educate patients regarding proper anal hygiene and to avoid chemical and mechanical irritants (1).
• High-fiber diet and/or bowel regimen to maintain regular bowel movements (1)
• Avoid tight-fitting clothing. Use cotton undergarments.
• Absorbent cotton, 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.
• Treat underlying anorectal anatomic pathology: banding of prolapsing internal hemorrhoids, treat fistulas, or fissures.
• 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. Avoid use >12 weeks due to risk of skin atrophy.
• If no response with low-potency steroid, consider high-potency steroid cream.
• Antihistamines, witch hazel may be useful until local measures take effect, particularly sedating antihistamines, which will reduce nighttime itching (4).
• Tricyclic antidepressants may reduce nighttime scratching
• Zinc oxide can be used after completing steroid course for barrier protection (3)[C]; petroleum jelly is another barrier treatment (mineral oil can worsen pruritus).
• Low-dose topical capsaicin cream in combination with steroid cream if refractory symptoms (1)[A]
• 0.1% tacrolimus ointment may be a good option for patients at risk for atrophy from prolonged steroid use.
• Several small case series have shown symptomatic benefit with methylene blue injection—this may be an additional option for patients with refractory itch.
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, or biopsies). 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.
• Refer for colonoscopy if at risk for colon cancer.
SURGERY/OTHER PROCEDURES
As above, especially if concern for malignancy identified
ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
See patient every 2 weeks if not improving. Ensure proper hygiene, and avoidance of irritants. Work up for systemic disease, and check for persistent lichenification. If refractory pruritus or lichenification 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 or dermatitis.
• 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 products with irritating perfumes and dyes.
– Avoid use of ointments and mineral oil.
– Wear loose, light cotton clothing.
– If moisture is a problem, use cotton, 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 caffeine, cola, chocolate, citrus, tomatoes, tea, beer/wine, nuts, milk products (3)[C].
• Evaluate for underlying medical disease.
• 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 successful in ~90% of cases
• Idiopathic pruritus ani often is chronic, waxing and waning.
COMPLICATIONS
• Bacterial superinfection at site of excoriations and potential abscess formation or penetrating infection via self-inoculation with colonic pathogens
• Lichenification
• Significant effect on quality of life
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. de Zoeten EF, Pasternak BA, Mattei P, et al. Diagnosis and treatment of perianal Crohn disease: NASPGHAN clinical report and consensus statement. J Pediatr Gastroenterol Nutr. 2013;57(3):401–412.
ADDITIONAL READING
• 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.
• Lacy BE, Weiser K. Common anorectal disorders: diagnosis and treatment. Curr Gastroenterol Rep. 2009;11(5):413–419.
• 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.
• 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.
SEE ALSO
CODES
ICD10
L29.0 Pruritus ani
CLINICAL PEARLS
• Pruritus ani is characterized by intense anal/perianal itching and/or burning.
• Usually idiopathic or related to skin irritation with itch–scratch–itch cycle
• Conservative treatment with good perianal hygiene and reassurance is successful in 90% of patients.
• Evaluate for systemic disease, and treat underlying anorectal pathology or other secondary causes.
• Consider trial of dietary elimination of “C”s—citrus, vitamin C supplements, calcium products, caffeine, coffee, cola, chocolate.
• Rule out infection (viral, bacterial, parasitic) in immunosuppressed patients.
• Consider underlying malignancy if refractory.