History

Fact Explanation
Perianal Itching As the name suggests pruritus meaning itch in latin, and ani referring to anus, hence itching in the perianal area is the commonest symptom. There are multiple reasons for itching, one of the most common reason is fecal soilage. the use of soap to wash the perianal area frequently exacerbates the problem. Soap takes the natural oil out of the skin and hence the itching.(1) Depending on the etiology the reason for itching varies, but majority of it is either due to or contributive to fecal soilage
History of Dietary irritants Caffeine, alcohol, chocolate, tomatoes, spices and citrus fruit. Some of these foods are known to cause relaxation of the lower oesophageal sphincter and therefore may contribute to internal anal sphincter relaxation and thereby cause or contribute to fecal soiling. (2)
History of Dermatological conditions Other skin disorders such as atopy, psoriasis, dermatitis and lichen sclerosis can affect any part of the skin including the perianal skin resulting in the itch. (2)
History of Systemic disease(Diabetes, Connective tissue disorders, HIV, etc) Predisposes to poor anal sphincter tone and infection (2)
History of Sexual history Sexual history should include inquiry about receptive anal intercourse or Sexually transmitted Infections such as herpes simplex virus (hsV) and genital warts. Latex condoms can cause a contact dermatitis and inadequate lubrication may cause minor skin trauma and consequent pruritus (2)
History of Anorectal conditions Anorectal conditions such as fissures, fistulas, papillomas, skin tags, hemorrhoids or prolapse may hamper efficient wiping of the anus allowing small particles of faeces to accumulate on the perianal skin and act as an irritant (3)
History of frequent diarrhea Diarrhea may contribute to fecal soilage and it may also cause perianal excoriation (2)
History of constipation Constipation may cause fissures, and thereby may hamper efficient wiping of the anus which contribute to the itch(2)
History of incontinence Incontinence adds onto fecal soilage, and thereby causing an itch (3)
Exposure to parasites Parasites can act directly on the skin or can add to fecal soilage causing the pruritus. Family members also might have been infected(3)
References
  1. SCHERGER JE. Responses to article regarding a diagnostic approach to pruritus. Am Fam Physician [online] 2012 May 1, 85(9):1; author reply 1-2 [viewed 16 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/22612190
  2. MACLEAN J, RUSSELL D. Pruritus ani. Aust Fam Physician [online] 2010 Jun, 39(6):366-70 [viewed 16 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/20628673
  3. JONES DJ. ABC of colorectal diseases. Pruritus ani. BMJ [online] 1992 Sep 5, 305(6853):575-577 [viewed 16 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1883300
  4. PFENNINGER JL, ZAINEA GG. Common anorectal conditions: Part I. Symptoms and complaints. Am Fam Physician [online] 2001 Jun 15, 63(12):2391-8 [viewed 16 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/11430454

Examination

Fact Explanation
Lichenification Due to excessive scratching leading to hypertrophy of epidermis (1)
Excoriation As a result of excessive scratching (2)
Bleeding perineum This is seen in severe form and due to scratching (2)
Hyperpigmentation As a result of chronic inflammation (1)
Skin tags, Hemorroids, fissures and fistula Causative factors for fecal soilage and hence the itch.(1)
Severe itch multiple lesions Due to herpes(1)
Involvement of labia and perineum Due to Lichen sclerosis(1)
Groin Lymph nodes Due to neoplasm or Sexually trasmitted diseases(1)
Distinct boundary of involvement of the itch Suggestive of tinea, psoriasis or neoplasia(1)
Bright erythema Suggestive of yeast infection(1)
Parasites visualised in the perianal region Suggestive of Parasitic infection(2)
References
  1. SIDDIQI S, VIJAY V, WARD M, MAHENDRAN R, WARREN S. Pruritus Ani Ann R Coll Surg Engl [online] 2008 Sep, 90(6):457-463 [viewed 16 September 2014] Available from: doi:10.1308/003588408X317940
  2. PFENNINGER JL, ZAINEA GG. Common anorectal conditions: Part I. Symptoms and complaints. Am Fam Physician [online] 2001 Jun 15, 63(12):2391-8 [viewed 16 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/11430454

Differential Diagnoses

Fact Explanation
Hemorrhoids Altered anal morphopathology leading to fecal soiling. Inability to evacuate their anal canals completely and the retained fecal material results in the itch (1)
Fissures Altered anal morphopathology leading to fecal soiling. Inability to evacuate their anal canals completely and the retained fecal material results in the itch(1)
Allergic contact dermatitis Due to sensitisation by chemicals found in cleansing and therapeutic preparations (2)
Infections Bacterial, Fungal, Parasitic and Viral infections can have a direct effect on the perianal skin.(3)
Dermatologic conditions Psoriasis, contact dermatitis, atopy, lichen sclerosus, seborrhea dermatitis, atopic dermatitis, etc, Can effect any part of the skin including the perianal skin(3)
Peri-anal Paget's disease or peri-anal Bowen's disease Malignancy can have a direct effect on the skin as well exacerbate fecal soiling and contribute to the pruritus(2)
References
  1. SIDDIQI S, VIJAY V, WARD M, MAHENDRAN R, WARREN S. Pruritus Ani Ann R Coll Surg Engl [online] 2008 Sep, 90(6):457-463 [viewed 16 September 2014] Available from: doi:10.1308/003588408X317940
  2. HEARD S. Pruritus ani. Aust Fam Physician [online] 2004 Jul, 33(7):511-3 [viewed 16 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/15301168
  3. MACLEAN J, RUSSELL D. Pruritus ani. Aust Fam Physician [online] 2010 Jun, 39(6):366-70 [viewed 16 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/20628673

Investigations - for Diagnosis

Fact Explanation
FBC Helps to diagnose infection, worm infestation and atophy (1)
Swabs for microscopy and culture To identify the causative agent of the infection if infections suspected (fungal, streptococcal, staphylococcal, gonococcal and corynebacterium infections) (1)
Syphilis serology When signs of possible syphilis infection such as condylomata lata, chancre, mucous patches seen. (1)
Patch tests If contact dermatitis is suspected (1)
Nocturnal cellotape test and/or stool test If worm infestation suspected (1)
Colonoscopy When there are any suspicious symptoms accompany pruritus, such as altered bowel habit or bleeding (1)
Anal polymerase chain reaction (PCR) swabs for Neisseria gonorrhoeae, C. trachomatis If at risk for STIs. (1)
PcR swabs taken from lesions for hsV, syphilis and vaginal swabs (vaginal discharge may cause anal pruritus) When syphilis suspected (1)
Biopsy of the area This is useful for diagnosing noninfective blistering skin conditions in patients not responding to conservative treatment and for investigating abnormal looking areas for cancer (1)
References
  1. MACLEAN J, RUSSELL D. Pruritus ani. Aust Fam Physician [online] 2010 Jun, 39(6):366-70 [viewed 16 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/20628673
  2. FARGO MV, LATIMER KM. Evaluation and management of common anorectal conditions. Am Fam Physician [online] 2012 Mar 15, 85(6):624-30 [viewed 16 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/22534276
  3. SCHUBERT MC, SRIDHAR S, SCHADE RR, WEXNER SD. What every gastroenterologist needs to know about common anorectal disorders World J Gastroenterol [online] 2009 Jul 14, 15(26):3201-3209 [viewed 16 September 2014] Available from: doi:10.3748/wjg.15.3201

Management - General Measures

Fact Explanation
Hygiene education Education can reduce pruritus ani in majority. Enabling the patients to identify the irritants and avoiding them is of paramount importance. The patients should also be adviced not to scratch to break the itch-scratch cycle Few other things are 1. Keep the anal area clean by washing after defecation. 2. Avoid medicated soaps which may cause sensitisation. 3.Dry the anal area by gentle dabbing rather than rigorous rubbing. Don't use lavatory paper-use moist tissues normally used for babies' bottoms. Scented powders should be avoided as they may be allergenic. 4. Use only specifically prescribed ointments as some keep the skin moist and may be allergenic. 5. Avoid impervious underwear such as acrylic and nylon garments which trap sweat. 6. Maintain a regular bowel habit and avoid highly seasoned and spiced food. 7. Wear cotton gloves at night to reduce the damage from subconscious scratching. (1)
Bulking agent Fibres and loperamide given to better the consistency of feces.(2)
Antihistamine Given in patients with nocturnal scratching.(2)
Antibacterial soap Used to clean the area. (3)
References
  1. JONES DJ. ABC of colorectal diseases. Pruritus ani. BMJ [online] 1992 Sep 5, 305(6853):575-577 [viewed 16 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1883300
  2. SIDDIQI S, VIJAY V, WARD M, MAHENDRAN R, WARREN S. Pruritus Ani Ann R Coll Surg Engl [online] 2008 Sep, 90(6):457-463 [viewed 16 September 2014] Available from: doi:10.1308/003588408X317940
  3. SCHUBERT MC, SRIDHAR S, SCHADE RR, WEXNER SD. What every gastroenterologist needs to know about common anorectal disorders World J Gastroenterol [online] 2009 Jul 14, 15(26):3201-3209 [viewed 16 September 2014] Available from: doi:10.3748/wjg.15.3201

Management - Specific Treatments

Fact Explanation
Weak topical steroid When conservative (health education alone is not sufficient) treatment fails (1) (need to exclude infections)
Capsaicin 0.006% cream When treatment with high dose steroids have failed (2)
Underlying cause If an underlying cause is found, then treating it will settle the pruritus
Mebendazole If threadworms discovered or identified in the effluent of a diagnostic saline enema.(3)
Topical lindane or malathion If pruritus is caused by Pediculosis pubis and scabies(3)
Antifungal agent if microscopic examination of skin scrapings confirm fungal infection (3)
References
  1. FARGO MV, LATIMER KM. Evaluation and management of common anorectal conditions. Am Fam Physician [online] 2012 Mar 15, 85(6):624-30 [viewed 16 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/22534276
  2. SIDDIQI S, VIJAY V, WARD M, MAHENDRAN R, WARREN S. Pruritus Ani Ann R Coll Surg Engl [online] 2008 Sep, 90(6):457-463 [viewed 16 September 2014] Available from: doi:10.1308/003588408X317940
  3. JONES DJ. ABC of colorectal diseases. Pruritus ani. BMJ [online] 1992 Sep 5, 305(6853):575-577 [viewed 16 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1883300