Equine Dermatology Engagement Session PDF

EQUINE D E R M AT O L O G Y ENGAGEMENT SESSION DR ALISSA COOPER BSC BVETMED PGCERTVETED FHEA MRCVS LECTURER IN EQUINE CLINICAL PRACTICE OTC CY-OI-IO LEARNING OBJECTIVES Discuss the presentation, diagnosis and treatment in relation to sarcoids in horses...

EQUINE D E R M AT O L O G Y ENGAGEMENT SESSION DR ALISSA COOPER BSC BVETMED PGCERTVETED FHEA MRCVS LECTURER IN EQUINE CLINICAL PRACTICE OTC CY-OI-IO LEARNING OBJECTIVES Discuss the presentation, diagnosis and treatment in relation to sarcoids in horses Discuss the presentation, diagnosis and treatment in relation to dermatitis in horses Discuss the presentation, diagnosis and treatment in relation to melanoma in horses Discuss the pathogenesis, diagnosis and treatment in relation to exuberant granulation tissue in horses 2 IT’S NOT ALL SARCOIDS AND SWEET ITCH Dermatology can be exciting and interesting! Welfare You can really make a difference to these animals and their owners Think logically and work systematically What are your differential diagnoses? ‘VITAMIN D’ Neoplasia it’s not always a sarcoid 3 ALSO NOT SARCOIDS… 4 CASE 1 A 12 year old Haflinger gelding presented with a lesion on the right caudal abdomen, as depicted below. The skin lesion had been present for 2 years with a slow and gradual growth pattern. It was gradually increasing in diameter and recently developed more thickening in the centre. 5 CASE 1 A 12 year old Haflinger gelding presented with a lesion on the right caudal abdomen, as depicted below. The skin lesion had been present for 2 years with a slow and gradual growth pattern. It was gradually increasing in diameter and recently developed more thickening in the centre. What other questions would you ask the owner? 6 CASE 1 What other questions would you ask the owner? Is it pruritic (itchy)? Are there other lesions? Where are they? Other horses affected? Any treatments tried? Any known cause? Any recent changes? General health? Preventative health? 7 CASE 1 Describe the lesion 8 CASE 1 Describe the lesion Well circumscribed Alopecic Epidermal thickening Hyperkeratotic Verrucous change centrally Pigment change Lichenification 9 CASE 1 What are your differentials? 10 CASE 1 What are your differentials? Sarcoid (occult/verrucous – mixed) Dermatophytosis Scar Chronic skin irritation/rubbing Automimmune disease – pemphigus (v. unlikely) 11 CASE 1 What diagnostics do you want to do? 12 CASE 1 What diagnostics do you want to do? Sking scrape/hair pluck – rule out other differentials Skin biopsy- incisional or excisional Beware of potential risks of making it worse Have a plan None? Prognosis? Good for resolution of this lesion Risk of new lesions relatively high 13 CASE 1- SARCOID Nodular Fibroblastic/malignant Nodular 14 CASE 1- SARCOID Verrucose/mixed Verrucose Occult 15 CASE 1 Treatment? 16 CASE 1 Treatment - Topical These lesions are often amenable to topical therapy AW5 cream (previously AW4- LUDES or Liverpool Cream) Provided by online referral to Equine Medical Solutions Bespoke treatment plan – generally good efficacy Forms hard eschar (a slough of dead tissue that sheds off) Local reaction painful as cytotoxic + Care where applied MUST be applied by a vet 17 CASE 1 Treatment – Topical Imiquimod (Aldara 5% cream) Immune modifier – amplifies local immune response Good response has been reported (verrucose/occult lesions) Minimal side effects (can be sore) Requires long course of therapy (4-6 months) 5-Flurouracil (Efudix 5% cream) Anti-metabolie that inhibits DNA replication Increased cytotoxicity – faster effect but increased local reaction Bloodroot – Sanguinaria canadensis (Newmarket Bloodroot Ointment, Xxterra) Currently applying for VMD license? 18 CASE 1 Treatment – Other Surgery Ligation/banding – A1/B1 Nodular sarcoids only WITHOUT a root or risk treatment failure Laser surgery Sharp resection Chemotherapy/Electrochemotherapy (Efudix 5% cream) Cytotoxic or chemotherapeutic agents Intralesional cisplatin, carboplatin, 5-FU, mitomycin C Electrical impulses increase cytotoxicity 80 fold 19 CASE 1 Treatment – Other Radiotherapy - gamma radiation is effective but costly Cryotherapy Immune modulation Photodynamic therapy Benign neglect - discuss consequences with owner 20 CASE 1 Treatment Warn owner that it may be a long road Some are surprisingly successful Invasive fibroblastic on muzzle Cryotherapy and Intralesional 5FU 21 CASE 1 Treatment – Periocular Sarcoids Topical/surgical treatment Can be difficult Depending on nature of lesion can use skin expanders to reconstruct lid Intralesional therapy BCG can be very effective intradermally Difficult to acquire Radiation 22 CASE 1 Molly – Periocular Sarcoid 23  C A S E 1 - T R E AT M E N T O P T I O N S Action Pros Cons Benign neglect Free, no painful intervention. (Can manage Sarcoids can get bigger/ulcerate, become more numerous and need discomfort/provide palliative tx with NSAIDs) action in future (small lesions always easier to treat than large lesions!). Sharp surgery Instant removal, debulk lesions prior to other treatment (eg High risk of recurrence if sole therapy (need large margins) intralesional chemotherapy, radiotherapy, etc) Ligation Cheap/easy Only suitable for certain types of nodular sarcoids. High recurrence rate. Laser Surgery Easier to get wide margins, higher success rate than sharp Equipment expensive. Left to heal by secondary intention – slow to resection. heal. Radiotherapy High success rate, no wide margin (as with surgery). Best Expensive, radioactive hazard – human safety option for peri-ocular sarcoids. E.g. HDR, strontium pleiotherapy etc. Topical Efficacy depends on drug – see previous slide. Local reaction (variable depending on drug, can be unpredictable). (chemo)therapeutic Human safety. Problems when used over blood vessels, or over inner agents thigh where can rub against the other leg. Intralesional High success rate due to cytotoxicity Local effects such as swelling, dangerous drugs, risk to human health. chemotherapy/electroc hemotherapy Cryotherapy Relatively cheap, useful adjunct with surgery or other Time consuming (3 x treatments), high recurrence rate if used alone, therapies painful/local reaction. 24 CASE 2 A 10 year old Welsh pony mare presented with a history of intense pruritus during the summer period, which has occurred over the last 3 seasons, and is noted to be getting more severe. The pony spends prolonged periods of time scratching the rump, tail and mane, resulting in self-induced alopecia and excoriations of the skin. Similar lesions (as depicted in the picture) are noted on the mane. What other questions would you ask the owner? 25 CASE 2 A 10 year old Welsh pony mare presented with a history of intense pruritus during the summer period, which has occurred over the last 3 seasons, and is noted to be getting more severe. The pony spends prolonged periods of time scratching the rump, tail and mane, resulting in self-induced alopecia and excoriations of the skin. Similar lesions (as depicted in the picture) are noted on the mane. What other questions would you ask the owner? How long have you owned her? Management? Stabled/turned out? What is turnout like? Do you use a rug? Any topical shampoos etc? Diet? Parasite control history Previous treatment 26 CASE 2 A 10 year old Welsh pony mare presented with a history of intense pruritus during the summer period, which has occurred over the last 3 seasons, and is noted to be getting more severe. The pony spends prolonged periods of time scratching the rump, tail and mane, resulting in self-induced alopecia and excoriations of the skin. Similar lesions (as depicted in the picture) are noted on the mane. What are your differential diagnoses? 27 CASE 2 Primary DDx: Culicoides hypersentivity - Sweet Itch Others Dermatophilus congolensis – Dermatophilosis/Rain scald Dermatophytosis - Ringworm Contact hypersensitivity HS to other flies/insects Louse infestation Diagnostic Plan? Culicoides sp. Flies - MONSTER HUNTER'S GUIDE TO: VETERINARY PARASITOLOGY 28 CASE 2 Diagnostic Plan Primary DDx: Culicoides hypersentivity - Sweet Itch Others Clinical Presentation – self-trauma, season Evaluate environment – stagnant water for breeding of Culicoides midge Hair plucks, skin scrapes, scurf examination Rule out ectoparasites Intradermal skin test Check for/rule out other allergens Biopsy Eosinophilic folliculitis and dermatitis 29 CASE 2 Treatment - Management Management changes to control or reduce exposure to the inciting cause Fly rugs/masks Fly repellent – permethrin/cypermethrin best Move field during summer months or remove body of water/improve drainage Stable during dawn and dusk (midges most active 4-8 pm) Fans in stable to maintain airflow – poor at flying! Start control measures BEFORE midge season begins Other – SSS/lotions/baths 30 CASE 2 Treatment - Therapeutics Medications to reduce severity of pruritic Anti-inflammatories Prednisolone/dexamethasone (systemic/topical) Beware long term or repeated us of steroid therapy Laminitis risk? Further reading on final slide Antihistamines licensed? Desensitization therapy – little evidence any better than avoidance Nutritional supplements 31 CASE 3 A 6 year old cob gelding presented with pruritus of the distal limbs. The signs developed after the horse moved yards a few weeks ago (September). The horse is stamping his feet, rubbing his legs and biting at his pasterns. There is no previous history of skin conditions reported. What other questions would you ask the owner? Describe the lesions 32 CASE 3 A 6 year old cob gelding presented with pruritus of the distal limbs. The signs developed after the horse moved yard a few weeks ago (September). The horse is stamping the feet, rubbing its legs and biting at the pasterns. There is no previous history of skin conditions reported. What other questions would you ask the owner? Describe the lesions Diffuse Alopecic Erythematous Scurf and Scale Exudative Skin Thickening Pruritic What would your diagnostic approach be and what is your top DDx? 33 CASE 3 Diagnostic Approach Sticky tape impression Skin scrape Hair pluck – rule out fungal Biopsy? Primary Differential Diagnosis Chorioptic Mange (Chorioptes bovis) Skin dwelling/scurf feeding mite Prevalent in house horses Daught/feathered breed over-represented ‘Outbreaks’ can occur due to spread via brushes and other shared equipment 34 CASE 3 Management advice? Clip the hair – owners may not be happy with this! Take out all bedding Clean and disinfect stable and keep changing bedding Treat in contacts Not always the horses that are stamping the most! Pig oil – (white mineral oil and yellow sulphur) patch test Stop sharing equipment! 35 CASE 3 Treatment? Thorough cleaning of the area with appropriate shampoo E.g. keratolytic shampoos or selenium sulphide shampoo prior to treatment Historically in UK - Doramectin (Dectomax) subcutaneous injection 2 doses 14 days apart Fipronil spray (only effective if clipped) Ivermectin/moxidectin Not licensed for horses Environment! Lime sulphur spray/dip – repeat q. 7-14 days as needed Aim is to control/manage 36 PA S T E R N D E R M AT I T I S Common cutaneous reaction pattern Not a single disease Many potential causes Differential Diagnosis of Pastern Dermatitis Bacterial folliculitis/furunculosis Dermatophilosis (mud fever) Spirochetes Dermatophytosis Chorioptic mange Trombiculiasis (harvest mites) Pelodera dermatitis Vaccinia Primary irritant contact dermatitis Allergic contact dermatitis Photosensitisation Trauma Vasculitis Pemphigus foliaceus Chronic progressive lymphoedema 37 Scott & Miller 2011 CASE 4 12 year old grey Connemara mare presented with several nodular masses in the perineal region and under the tail, which have been gradually increasing in size over the past 6-8 months. Clinical exam additionally revealed further nodular masses on the right groin region and a raised swelling in the left parotid region. Differentials? Diagnostics? Treatment? Equine Dermatology | Date | Version 1.0 38 CASE 4 Differentials Melanoma* Sarcoid Mast cell tumours etc. Diagnostics FNA: pleopmorhic and atypical melanocytes Biopsy: atypical melanocytes 39 MELANOMA Treatment options Surgical removal – easier when lesions are small so don’t wait until they grow! Treatment of choice and usually curative Can be difficult in certain areas Diode laser Chemo-/electrochemo-/thermochemo-therapy Cryosurgery Oncept vaccine? Tyrosinase inhibitor (expensive and limited evidence) Autologous vaccine USA Cimetidine Benign neglect 40 MELANOMA Beware benign neglect! Do NOT underestimate melanomas Should be considered ‘pre-cancerous’ rather than ‘benign’ as they all have the potential to become malignant Other neoplasia – see references Beware amelanotic 41 melanomas… D E R M ATO P H Y TO S I S ( R I N G W O R M ) Fungus, not parasite! Trichophyton equinum and Trichophyton mentagrophytes Contagious Outbreaks possible Source of great worry for horse owners Another reason to not share equipment! Zoonotic - PPE Diagnosis Fungal culture – slow results 2-3 weeks - start treatment Fungal qPCR – rapid 1 day Treatment Enilconazole washes Remove crusts first Dilute per instructions 3 day intervals, 4 repeats First treatment – treat whole horse 42 E X U B E R A N T G R A N U L AT I O N T I S S U E Proud flesh History of wound Location – lower limbs Poor skin mobility and frequent movement Limited wound contraction Proliferation of haemorrhagic granulation tissue Diagnosis – History, CE +/- biopsy DDx – Sarcoid, papillomatosis, Habronemiasis (not so much UK), bacterial or fungal granulomas, SCC Rule out underlying cause of non-healing would E.g. bone sequestrum, infection, tumour, foreign body, underlying condition Treatment Debride Topical corticosteroids? Bandage, keep clean Restrict movement 43 URTICARIA-HIVES Equine urticaria: a clinical guide to management – Diesel - 2014 - In Practice - Wiley Online Library 44 RECORD KEEPING Dermatological exam sheet Effective monitoring Good record keeping Aids surgical planning Can track changes in size Helps owner know what they are monitoring Give me a call if… Pre-purchase exams 45 REFERENCES/FURTHER READING Treatment of equine sarcoids: A systematic review - Offer - 2024 - Equine Veterinary Journal - Wiley Online Library Equine Medical Solutions Ltd | Equine Sarcoid Advice What is the most effective treatment in horses with chorioptic mange? (oclc.org) Diagnosing and treating ringworm in horses - Durham - 2020 - In Practice - Wiley Online Library Equine urticaria: a clinical guide to management - Diesel - 2014 - In Practice - Wiley Online Library Melanoma in horses: Current perspectives - Moore - 2013 - Equine Veterinary Education - Wiley Online Library 46