Equine Skin Disease Flashcards
What species of lice affect horses?
Damalinia equi (biting) Haematopinus asini (sucking)
What time of year do lice infestations of horses occur?
Winter
How are lice infestations treated in horses?
Cypermethrin spray/sponge on whole body
Permthrin and citronellol sponge
Piperonyl butoxide shampoo
Suitable insecticides for grooming kit, blankets and stable area
Why should pyrethrins be dispoesd of very carefully?
They are extremely toxic to aquatic life
What is the most common mange in horses?
Chorioptic
What species causes mange in horses?
Chorioptes bovis
where do chorioptic mange lesions occur in the horse?
Distal limb of horses with feathered heels
What is the most likely cause of reinfestation of chorioptic manage in horses?
From the env
Are there any licensed products for treating chorioptic mange in horses?
No
What can be used to treat chorioptic mange in horses?
All off license:
- Oral ivermectin (NOT SPRAY)
- Selenium sulphide shampoo
- Fipronil spray
- Flumethrin (sheep dip)
Which durg is absolutely contraindicated for treating demodex in equidae and why?
Amitraz - alters gut motility leading to colic
What is the proper term for sweet itch?
Culicoides hypersensitivity
Recurrent seasonal pruritis
What is Culicoides?
Midge
Why is sweet itch a significant disease?
Welfare
Management problems
What are the clinical signs of sweet itch?
Pruritus and lesions along the dorsal midline, mane and tail and sometimes ventrally
What treatment is licensed for sweet itch?
Benzyl benzoate solution
Why are permethrins a poor choice for treating sweet itch?
Need frequent application - expensive
What is the most effective method of preventing sweet itch? How can this be achieved?
Prevention of midge feeding
- Stable horses at dawn and dusk
- Ceiling fans
- Insecticidal strips
- Graze on well drained land away from standing water
- Fly repellant ear tages tied to head collar
- Rugs with hoods
Which mites affect horses?
Red mite
Harvest mite
What are infectious causes of pastern dermatitis syndrome?
Bacteria
Fungi
Parasites
What are non-infectious causes of pastern dermatitis syndrome?
Physical
Neoplasia
Immune-mediated
Miscellaneous - greasy heel syndrome
What are the clinical signs of pastern dermatitis in horses?
Back of pastern
>1 leg
Papules => large areas of ulceration and suppuration
How is pastern dermatitis diagnosed in horses?
History and clinical signs
Biopsy
Bacterial and fungal culture
How is pastern dermatitis treated?
Remove crust and clip hair thoroughly
Wash with antiseptic surgical scrub
Antifungals, anti-inflammatories and AB
Corticosteroids
What are the characteristics of where greasy heel lesions are found?
Posterior of hind pastern
White-socked
May extend to fetlock and front of leg
May affect more than one leg
What breeds is greasy heel more common in?
Feathered breeds
Draught horses
What are the clinical signs of greasy heel?
Erythema Oozing, crusting Alopecia Vasculitis Erosion and ulceration Thickening of skin Pruritus Granulation tissue Pain, lameness
How is greasy heel treated in horses?
Eliminate all possible causes Topical antiseptic washes Removal of all hair and necrotic tissue Keep as dry as possible NSAIDs, AB
Where on the body of equids are Chorioptes spp and Psoroptes spp found?
c - Limbs and tail
p - Head and ears
What species of pinworm affects horses?
Oxyuris equi
What is the most common skin allergy in horses?
Sweet itch
What are the most common bacterial skin infections of horses?
Staph Dermatophilus congolensis (mud fever/rainscald)
What is the appearance of Dermatophilus congolensis microscopically?
Train-track bacteria
What type of virus causes aural plaques in horses?
Papillomavirus
What immune-mediated disease affect horses in dermatology?
Pemphigus foliaceus Erythema multiforme ADRs Vasculitis Alopecia areata
What are the clinical signs of Cushing’s/PPID in horses?
Old age PUPD Lethargy Laminitis Thick, dark excessive hair growth
