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Prurtius ani is defined as a dermatological condition characterized by an unpleasant itching or burning sensation in the perineal region ( Billingham RP et al 2004 ). Its a Latin term for itchy anus.
How common – It affects 1-5 % of the population Four times more common in men Most frequent between 4th -6th decades of life The patient is often anxious and / or over weight with a colonic reflx associated with stress Patients often attribute this to poor hygeine and wold have tried various measures as vigorous washing with soap extended cleansing with dry toilet paper using baby wipes scratching with fingernails generous use of creams , ointments or other agents Most sufferers have a relapsing and remitting course although some have severe symptoms with significant impact on QOL.
Types – Pruritus ani of unknown cause- Primary or Idiopathic pruritus ani. Responsible for 50-90 % of all cases and considered to be functional or psychological in nature.
Secondary pruritus ani- causes include infectious , dermatological , systemic , local irritants , anorectal .
History- Onset , duration of symptoms any pattern ? e.g more at night any one else in the household affected ? medical history for e.g any systemic illness dermatological history bowel habit ( ask about symptoms suggestive of haemorrhoids , fissure , bleeding , discharge , irritability ) medication history dietary history family history sexual history psychological / psychiatric history – impact on QOL social history personal hygiene history for e.g use of use of potential irritants , foods , drinks , clothing , creams , perfumes , soaps.
Examination –Examination needs to be based on clinical suspicion and can range from a full systemic exam to a limited examination of the anorectal region. A brief examination of the ano-rectal region is discussed here ask for consent / chaperon examine in lateral position to allow a comfortable view of the region observe for any obvious signs of haemorrhoids , eczema , excorciation, fissure , discharge , irritability pubic hair for lice any warts , abscess , ulceration , erythema , faecal soiling skin lichenification due to repeated scratching consider a DRE if any suspicion of anorectal cancer.
Tests –Generally no investigations are needed in primary care. Based on clinical suspicion the following may be considered FBC ( r/o infection , atopy ) IgE scrapping of erythematous plaques for fungal examination biopsy of suspicious lesions investigation if an underlying systemic cause is suspected eg diabetes , coeliac disease swabs and cultures of ulcerated lesions for exclusion of STIs ( e,g syphilis ) patch test if contact dermatitis is suspected nocturnal cellotape test and or stool test for helminthes conoloscopy if anorectal cancer is suspected.
General approach –Most treatment of puritis ani is based on experience and expert opinion. Good quality evidence to support a particular regimen over other is lacking. If no secondary cause is found – treat as primary or idiopathic type The condition can be difficult to manage Treatment may involve a trial and error approach Managing patients expectations should be important The goal of treatment is asymptomatic dry , intact, clean , peri-anal skin with reversal of morphological skin Newer therapies like Tacrolimus and capsaicin have not proven to be effective , anal tattoing is promising.
Complications –Skin changes due to persistent itching as excoriation , lichenification , ulceration , infection Averse impact on mental health , trouble sleeping Impact on QOL.
Treat any underlying cause –treat any anorectal condition infections constipation refer to secondary if the underlying cause cannot be managed in primary care.
Elimination step –eliminate any irritants advice not to scratch toilet paper soaps/ creams bubble bath shampoo in bath certain foods/ drinks.
Ensure regular bowel habit –adequate fluids fiber , balanced diet regular bowel movements manage if constipated.
Provide symptom relief – antihistamines – consider peparation with sedating properties if disturbed sleep prescribe soothing cream or ointment containing bismuth subgallatate or zinc oxide , topical corticosteroids , haemorrhoidal preparations as needed.
Self care measures – provide written information – find it under links and resources advice that in most people symptoms would improve with self care and symptomatic treatment self care measures can be relaxed after 2 months if symptoms improve
Seek help- refer consider further investigations if self care measures and symptomatic treatment fails to improve symptoms after 3-6 weeks Consider referral to an anorectal surgeon if no cause is found for further assessment.
LINKS AND RESOURCES
PATIENT INFORMATION
BAD leaflet on pruritus ani http://www.bad.org.uk/shared/get-file.ashx?id=120&itemtype=document
Association of coloproctology of Great Britain and Ireland -leaflet https://www.acpgbi.org.uk/content/uploads/2018/12/Pruritus.pdf
Colorectal surgical society of Australia and New Zealand https://cssanz.org/index.php/patients/pruritis-ani
American Society of Colon and rectal surgeons with a helpful video https://fascrs.org/patients/diseases-and-conditions/a-z/pruritus-ani
A good explainer from colorectal centre co uk https://colorectalcentre.co.uk/pruritus-ani-itchy-bottom.html
INFORMATION FOR CLINICIANS
Information from ASCS https://fascrs.org/patients/diseases-and-conditions/a-z/pruritis-ani-expanded-version
A good open-access review article https://www.ommegaonline.org/article-details/A-Review-of-the-Therapeutic-Interventions-in-the-Management-of-Pruritus-Ani/1220
–References
- CKS NHS pruritus ani 2016
- Pruritus ani by Joanne McLean RACGP Vol 39 , No 6 , June 2010
- Pruritus Ani by S Siddiqi et al Ann R Coll Surg Engl . 2008 Sep ; 90 (6) : 457-463
- Pruritus Ani review article Parswa Ansari MD , FACS , FASCRS Clin Colon Rectal Sur 2016 ;29: 38-42
- A review of the Therapeutic interventions in the management of Pruritus Ani Investigative Dermatology and Venereology Research January 2010