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M62 Course – Cedar Court Hotel, Huddersfield 7th April 2005 The Dermatologist and Pruritus Ani MJ Harries and CEM Griffiths Dermatology Centre, Hope Hospital, Manchester, UK “An unpleasant cutaneous sensation that induces the desire to scratch the skin” Itch-Scratch Cycle DAMAGED PERIANAL SKIN PRURITUS SCRATCHING Classification of Itch Pruritoceptive itch Originates in the skin Neurogenic itch Originates in the nervous system Itch specific neuronal pathway (C-fibres and spinothalamic tracts) Yosipovitch et al. Lancet 2003; 361:690-694 Causes of Pruritus Ani Anal pathology Infections Skin disease Contact allergy Underlying medical conditions Idiopathic Causes of Pruritus Ani Anal pathology Infections Skin disease Contact allergy Underlying medical conditions Idiopathic Skin Disease 85% consecutive patients referred to a combined colorectal and dermatological clinic had an underlying dermatosis Over half had a positive patch test “Patients with long-standing pruritus ani with no other symptoms to suggest colorectal pathology should be referred to a dermatologist for assessment and patch testing.” Dasan et al. Br J Surg 1999; 86: 1337-40 Psoriasis 2% population Approx. 1.2 million sufferers in the UK Immune-mediated disease Positive family history common Psoriasis Symmetrical Extensor aspects Elbows / knees Scalp Umbilicus Natal cleft 44% perianal involvement Farber et al. Dermatologica 1974;148:1-18 Psoriasis - Perianal Psoriasis - Perianal Where else to look? Where else to look? Lichen Planus Idiopathic inflammatory disease of the skin and mucous membranes Common sites Flexor wrist Anterior lower leg Neck Presacral area 75% oral involvement Lichen Planus Polygonal, violaceous, flattopped papules Wickham’s striae Pruritus +++ Lichen Planus - Perianal Lichen Planus - Perianal Where else to look? Where else to look? Lichen Sclerosis Idiopathic inflammatory disease that preferentially affects the anogenital region Hypopigmented and atrophic skin Figure-of-eight distribution (women) 5% risk of SCC Lichen Sclerosis - Perianal Seborrheic Eczema Link with sebum overproduction and the commensal yeast Malassezia furfur Red-brown patches with “greasy” scale Common sites Scalp Nasolabial folds Central chest / back Flexures Where else to look? Lichen Simplex – The Itch that rashes Itching often localised to one site resulting in lichenification Itch / scratch cycle develops Common sites Perineum Scrotum / vulva Posterior neck Lateral lower legs Lichen Simplex - Perianal Allergic Contact Dermatitis 55 / 80 (69%) clinically relevant allergic reactions 38 of these reactions to medicaments or their constituents Improvement or resolution of symptoms in ¾ patients with avoidance advice Advise patch testing at an early stage Harrington et al. BMJ 1992; 305: 955 Eczema - Perianal Patch Test Common allergens placed into Finn chambers 35 common allergens tested in the BCDS standard series Extra allergens tested in the perineal series Type IV delayed hypersensitivity response Patch Test – 0h Patch Test – 48h Patch Test – 96h Grading system for reactions Negative +/- Doubtful + Weak ++ Strong +++ Very strong Common Perianal Allergens Local anaesthetics Corticosteroids Neomycin Perfume Preservatives Antiseptics Goldsmith et al. Contact Dermatitis 1997; 36: 174-5 Pruritus Ani and Underlying Medical Conditions Consider a “pruritus screen” if generalised itch is also present Common causes include Iron deficiency Renal failure Hepatic/ biliary disease Malignancy FBC Ferritin / serum Fe / % sat / TIBC ESR U&E LFT TFT Glucose Calcium Serum electrophoresis CXR Idiopathic Pruritus Ani Faecal contamination Difficulty in cleaning the area Anal sphincter dysfunction Farouk et al. Br J Surg 1994; 81: 603-606 Dietary causes Lumbosacral radiculopathy 16 / 18 (80%) lubosacral radiculopathy confirmed by N.C.S Paravertebral injections of steroid / lignocaine resulted in reduced pruritus Cohen et al. J Am Acad Dermatol 2005; 52 :61-6 Treatment - General Advice Wash after every B.O and twice a day Avoid irritants Keep the area dry Wear cotton underwear Keep bowels regular Alexander-Williams J. BMJ 1983;287:1528 Topical Steroids Mild, moderate, potent and very potent Treats inflammation Break the itch-scratch cycle As control is achieved the potency should be reduced If not improving consider ?Appropriate potency for condition ?steroid allergy – Patch test ?correct diagnosis - Biopsy Other Treatments Topical Capsaicin Placebo controlled trial 0.006% capsaicin cream t.d.s for 4 weeks 31 / 44 (70%) responded Lysy et al. Gut 2003; 52: 1323 – 1326 Intradermal methylene blue injections 1% methylene blue / hydrocortisone / lignocaine 88% patients responded Botterill et al. Colorectal Dis 2002;4:144-6 Summary Examine the entire skin surface including nails and mucous membranes Consider patch testing early in management Consider skin biopsy if any diagnostic doubt or if the condition is not responding to appropriate treatment