- Intense anal/perianal itching and/or burning
- Usually acute (defined as <6 weeks of symptoms)
- Classified as primary (idiopathic) or secondary (25–75% of cases) to anorectal pathology (1)
- 1–5% of the general population (1)
- Predominant age: 30 to 50 years; although seen in all ages groups (1)
- Predominant sex: male > female (4:1) (1)
Difficult to estimate because many patients do not report symptoms; affects 1–5% of the population
Etiology and Pathophysiology
- Multiple etiologies categorized by inflammatory, infectious, systemic, neoplastic, neuropathic, neurogenic, and psychogenic causes (1),(2),(3)
- Most cases are idiopathic (25–90%), which are likely due to trauma from wiping or scratching and perianal fecal contamination (1).
- Pruritus may create an irresistible desire to scratch, leading to a self-perpetuating “itch–scratch–itch” cycle.
- Depending on underlying etiology, itch pathway may be histamine mediated or nonhistamine mediated (2).
- Pruritus ani is typically intensely perceived by the patient due to dense innervation.
- Consider primary pruritus ani when no other demonstrable causes can be found, including:
- Poor anal hygiene
- Loose or leaking stool that makes hygiene difficult. Patients with abdominal ostomy bags typically do not complain of pruritus.
- 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)
- Hidradenitis suppurativa
- Radiation dermatitis (3)
- Colorectal/anorectal diseases: rectal prolapse, hemorrhoids, fissures or fistulas, proctitis, 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, leukemia, lymphoma, or (uncommon) the presenting symptom of Bowen or Paget disease
- Mechanical factors: vigorous cleaning and scrubbing, tight-fitting clothes, synthetic undergarments
- Systemic diseases (often presents as generalized pruritus): diabetes mellitus (most common), cholestasis, chronic liver disease, renal failure, hyperthyroidism, anemia, HIV, vitamin or iron deficiencies, lumbosacral radiculopathy (particularly in the elderly).
- Chemical irritants: local anesthetics, 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
- Inflammatory dermatologic diseases:
- Excess perianal hair growth and/or perspiration
- Underlying anorectal pathology
- Atopic disease
- Underlying anxiety disorder
- Caffeine intake has been correlated with symptoms.
- Good perianal hygiene; avoid overzealous 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 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
There's more to see -- the rest of this topic is available only to subscribers.
Domino, Frank J., et al., editors. "Pruritus Ani." 5-Minute Clinical Consult, 27th ed., Wolters Kluwer, 2020. www.unboundmedicine.com/5minute/view/5-Minute-Clinical-Consult/116496/all/Pruritus_Ani.
Pruritus Ani. In: Domino FJF, Baldor RAR, Golding JJ, et al, eds. 5-Minute Clinical Consult. Wolters Kluwer; 2020. https://www.unboundmedicine.com/5minute/view/5-Minute-Clinical-Consult/116496/all/Pruritus_Ani. Accessed June 4, 2023.
Pruritus Ani. (2020). In Domino, F. J., Baldor, R. A., Golding, J., & Stephens, M. B. (Eds.), 5-Minute Clinical Consult (27th ed.). Wolters Kluwer. https://www.unboundmedicine.com/5minute/view/5-Minute-Clinical-Consult/116496/all/Pruritus_Ani
Pruritus Ani [Internet]. In: Domino FJF, Baldor RAR, Golding JJ, Stephens MBM, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2020. [cited 2023 June 04]. Available from: https://www.unboundmedicine.com/5minute/view/5-Minute-Clinical-Consult/116496/all/Pruritus_Ani.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Pruritus Ani ID - 116496 ED - Domino,Frank J, ED - Baldor,Robert A, ED - Golding,Jeremy, ED - Stephens,Mark B, BT - 5-Minute Clinical Consult, Updating UR - https://www.unboundmedicine.com/5minute/view/5-Minute-Clinical-Consult/116496/all/Pruritus_Ani PB - Wolters Kluwer ET - 27 DB - 5-Minute Clinical Consult DP - Unbound Medicine ER -