Editing Pruritis ani

'Unpleasant itching and burning of perianal skin'

* Typically worse at night or     in warm, moist climates

== '''Secondary pruritus ani''' ==

* '''Infectious'''
** Bacterial
** Fungal
*** Candida responsible for up       to 15%
*** Especially in       immunosupressed, on Abx, on steroids
*** Diffuse, erythematous,       macerated plaques
*** Dermatophytes
*** Treat with topical or       systemic antifungals
** STI
*** Gonorrhoea
*** Chlamydia
*** Syphilis
** Parasites
*** Esp nocturnal symptoms in       children - pinworms
*** Scabies
*** Crabs
** Viral
*** HSV
*** HPV - condyloma
*** HZ + shingles
* '''Anorectal'''
** Chronic inflammation
*** Pilonidal disease
*** Perianal Crohns
*** Hidradenitis suppuritiva
** Faecal contamination
*** Haemorrhoids
*** Fistula-in-ano
*** Anal fissures
*** Faecal incontinence
*** Skin tags
*** Chronic diarrhoea
* '''Dermatologic'''
** Contact dermatitis
*** Ask about cleaning       products/hygiene
** Atopic dermatitis
*** Ask about other atopy
** Perianal psoriasis
*** Scalp, flexor surfaces
** Lichen sclerosis
**** Commonly perimenopausal women, but can be associated with other autoimmune conditions
**** Probably also have vulvovaginal pruritis
**** Can give topical steroids - betamethasone topical (Diprosone 0.05%) daily for two weeks, then not more than twice a week to avoid skin atrophy
**** Barrier ointment like vaseline
**** Avoid harsh toilet paper, microtrauma of any form
**** Beware of malignant transformation into SCC - 5% lifetime risk
** Seborrheic dermatitis
** Radiation dermatitis
* '''Malignant'''
** Anal canal cancer
** Anal margin cancer
** Rectal cancer
** Bowen's disease
** Extramammary Paget's      (cutaneous adenocarcinoma in situ)
* '''Systemic     disease'''
** Diabetes
** Leukaemia
** Lymphoma
** CKD (uraemia - only cure is      kidney transplant)
** IDA
** Hyperthyroid
** Hyperbilirubinaemia -      ?cholestyramine

== Idiopathic ==

* '''Diagnosis of     exclusion'''
* Likely caused by faecal     contamination leading to local irritation
** Chronic diarrhoea
** Poor hygiene or overzealous      hygiene
** Faecal incontinence
** Mucus leakage
** ?Pruritogenic foods
* 'Itch-scratch cycle' likely     feeds into the chronic nature of this condition

== History should be thorough ==

* Onset and duration
* Toileting behaviours
* Mucus leakage or perianal     moisture
* Travel history
* Medications and allergies

== Workup ==

* Biopsy suspicious lesions
* Bacterial and fungal swabs
* Tape test for pinworm?

== Simple management suggestions ==

* Shower after opening bowels     and pat dry with unscented TP
* If moist area, consider talc     powder
* Treat any chronic diarrhoea     with fibre supplements
* Avoid tight-fitting garments     and perfumed products
* Try to avoid scratching
* Can trial topical steroids

== Second-line therapy: ==

* Topical capsaicin (0.006%)     TDS for 4 weeks - desensitises skin - seems to work up 70% of patients
* Topical tacrolimus has been     tried
* Intradermal methylene blue -     directly toxic to sensory nerves


[[Category:Colorectal]]