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M62 Course – Cedar Court Hotel, Huddersfield 7 th 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.
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M62 Course – Cedar Court Hotel, Huddersfield 7th April 2005The 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”
Pruritoceptive itch Originates in the skin Neurogenic itch Originates in the nervous system Itch specific neuronal pathway (C-fibres and spinothalamic tracts) Classification of Itch 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
Lichen Planus • Idiopathic inflammatory disease of the skin and mucous membranes • Common sites • Flexor wrist • Anterior lower leg • Neck • Presacral area • 75% oral involvement
Polygonal, violaceous, flat-topped papules Wickham’s striae Pruritus +++ Lichen Planus
Lichen Sclerosis • Idiopathic inflammatory disease that preferentially affects the anogenital region • Hypopigmented and atrophic skin • Figure-of-eight distribution (women) • 5% risk of SCC
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
LichenSimplex – 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
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
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
Grading system for reactions - Negative +/- Doubtful + Weak ++ Strong +++ Very strong Patch Test – 96h
Common Perianal Allergens • Local anaesthetics • Corticosteroids • Neomycin • Perfume • Preservatives • Antiseptics Goldsmith et al. Contact Dermatitis 1997; 36: 174-5
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 Pruritus Ani and Underlying Medical Conditions
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
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 Treatment - General Advice
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