Equine dermatological ID Flashcards
(47 cards)
1
Q
Name the 3 major bacterial dermatological diseases in horses
A
o Streptococcal dermatitis
o Staphylococcal dermatitis
o Dermatophilosis
2
Q
Name the 2 major Fungal dermatological diseases in horses
A
o Dermatophytosis (ringworm) o Subcutaneous / systemic
3
Q
Name the 3 major Viral dermatological diseases in horses
A
o Viral papilloma o Pinnal acanthosis / aural plaques o Coital exanthema o Horse pox o Papular dermatitis o (Sarcoid)
4
Q
Streptococcal Dermatitis
How common?
A
- Most common secondary infection of wounds and other skin damage
- Streptococcal part of normal flora, only pathogenic if primary infection compromising the horse immune system
- there are 3 diff types
5
Q
The different types of streptococcal dermatitis
A
- Streptococcus equi var. zooepidemicus:
- Most common type of streptococcus
- Opportunistic pathogen – if the skin is broken
- Folliculitis, furunculosis, cellulitis - Streptococcus equi var. equi: causes strangles
- Obligate pathogen
- Abscess (Bastard strangles) - Streptococcus equisimilis:
6
Q
Clinical signs Streptococcal dermititis
A
- Secondary infection to skin
- Mildly to moderately painful skin infections and abscess – secondary to the initial break in the skin
- Degree of discomfort tend to be mild
7
Q
How to diagnose Streptococcal dermatitis
A
- Based on culture and clinical features
* Sample of bacteria – sent for culture sensitivity
8
Q
Treatment of Streptococcal dermatitis
A
- If give antimicrobials give penicilin as v sensitive to it (almost 100% will resolve)
- If abscess then always drain
- Topical antimicrobial washes in mild superficial infections
9
Q
Presented with mild superficial streptococcal dermatitis infection. What treat and what to ensure?
A
- Topical antimicrobial washes
- Always make sure water is very warm, as hot as you can tolerate with hand.
- Heat helps penetration of antimicrobial on hair follicles
10
Q
StAPHYLOcoccus dermatitis
- which are most common?
A
Bacterial caused dermatitis
- Staphylococcus aureus and intermedius
- aureus of which can be resistant to a few antimicrobials
11
Q
Clinical signs horse has Staphylococcus
A
- Very painful to touch (different to Streptococcus) should immediately alert you to Aureus
- Localised exudative dermatitis
- Focal lesions also occur (abscesses or pyogranulomas)
12
Q
Difference between staphylococcus adn streptococcus?
A
Strepto - mild discomfort
Staphylo - Very painful
13
Q
Clinical syndromes associated with staphylococcus
A
- Pyoderma:
• Secondary to some form of trauma
• Large painful exudative areas - Saddle rash:
• Associated with rubbing of harness areas and saddle cloths - Pastern folliculitis picture on RHS
• Lots of things cause but secondary infection with staphylococcus complicates it - Abscesses
- These secondary infections tend to complicate!
14
Q
Treatment of staphylococcus
A
- Problematic! frequently become resistant to antimicrobials
- Clipping hair + antiseptic washes with warm water Always helps
- Drainage of abscesses
- Systemic antimicrobials based on c+s
- Tend to become resistant
15
Q
Talk about Dermatophilosis
A
- Bacterial caused dermatitis
- known as rain scald
- Bacteria called Dermatophilus congolensis
- not v pathogenic bacteria - needs breakage of skin
- very contagious, esp wet areas, young horses, groups
16
Q
What areas are most commonly infected by bacteria Dermatophilosis
A
• Affects areas that are commonly or persistently soaked – rain makes skin more susceptible to infection/damage: back, head and neck
17
Q
Presentation of rain scald/ dermatophilosis
A
- Initially lesions are small, easier to feel than see so might miss (common presentation in summer).
- Feel little scabs. Can sometimes see the hair is elevated
- More severe disease in winter: matted hair, adherent crusts with bits of matted hair a purulent base
- Bitch scab, hair comes and purulent base
- Pain usually mild
18
Q
Diagnosis of dermatophilosis
A
(Rain scald)
• Easily recognised clinically – pull scab off and the hair comes with it
• To confirm can direct smears
• Culture – characteristic tramlines
19
Q
Treatment dermatophilosis
A
- dry environment!! – skin can recover/heal better if dry
- Removal of every single matted hair and crusts/scabs
- Once removed, treat with antimicrobial washes (diluted chlorhexidine)
- Systemic antimicrobials in severe cases
20
Q
NAme 2 fungal dermatitis
A
o Dermatophytosis (ringworm) o Subcutaneous / systemic
21
Q
Talk about equine Dermatophytosis how common? contagious or not? incubation period? What horses mostly affected?
A
RINGOWRM!!
• One of the commonest skin disease affecting horses
• Highly contagious (direct and indirect contact – brushes, rugs, tack), groups of horses, immunocompromised horses (cushings)
• Incubation period 2-3 weeks
• Affects mostly young horses or immunosuppressed horses
• Some immunity with age. Older horses can be re-infected but lesions are smaller and quicker to resolve. More severe in younger horses
22
Q
What are the 2 main genera of fungi causing dermatophytosis/ ringworm?
A
Genera and then the most common species of each:
- Trichophyton:
- T. equinum var. equinum
- T. verrucosum
- Microsporum:
- M. gypseum
- M. equinum
23
Q
Clinical signs of equine dermatophytosis?
A
RINGERSSSSS
• Small (5-20mm), circular patches of hair “sticking” up – hair will become weak, fall or pull away easily.
• Accumulation of keratinised squamous cells: “cigarette ash”
• Weakening of hair → bald patches
• Secondary bacterial infections?
• Healing centrifugally from centre of lesion
• Young horse on RHS – severely infected
24
Q
diagnosis equine dermatophytosis?
A
- Skin scraping (+ microscopy)
- Hair pluck (+ microscopy)
- Culture (fungal culture takes a long time! Several weeks!)
- PCR recent develop – sample of hair and can detect genetic material of fungi. Quicker, however risks false negatives
25
Treatment equine dermatophytosis
* Isolate horse! Highly contagious and zoonotic (wear protective gloves)
* Most self limiting: 5-10 weeks for immunity and recovery – can take a long time
* Topical treatment: natamycin, enilconazole most common, done topically (bathe horse and environment/enrichment), miconazole
* Environmental disinfection – treat environment as fungal spores everywhere- Tack, brushes, rugs
26
Viral equine diseases
1. Viral Papilloma / Grass warts
2. Coital exanthema
3. Pinnal acanthosis/ Aural plaques
27
Talk about Viral Papilloma
1. also known as grass warts
2. an EQUINE SPECIFIC papovavirus
3. • Affects mainly younger horses (6 months to 4 years) or immunocompromised, hardly ever adults as good immunity, if adult big immunocompromise
• Moderately contagious
COMMON
28
Clinical signs of viral papilloma
(grass warts)
• Multiple pink or grey lesions on muzzle, lips, face, distal limbs, ventral abdomen and genital areas
• Affected animals show no evidence of discomfort or pruritus
29
Diagnosis of viral papilloma and treatment
Clinical diag
Treatment - often surgery or topical treatment causes more pain so usually leave adn spontaneous resolution will occur (may persist in older)
• Surgical excision if really affecting horse but can cause more damage
• Topical antivirals can cause inflammation
• Autogenous vaccination – freeze
30
Pinnal acanthosis
Viral disease
| Also called aural plaques
31
Is equine Pinnal acanthosis common?
| How transmitted?
* Very common – horses ears
* Unidentified Papillomavirus
* Transmission by black flies (Simulium spp.)
* Range from small raised depigmented areas to large clusters of white masses – raised plaques in the horses ears.
32
Diagnosis and treatment Pinnal acanthosis / Aural plaques
Diag: Straightforward = horse with plaques in ear
• Don’t mix with sarcoids!
Treatment:
Do not biopsy!!! horses don't like their ears being touched – could lead to very head shy horse.
DON't TREAT
33
Coital exanthema
What causes it?
transmissoon
Incubation
VIRAL disease
1. Venereal disease (sexually transmitted) caused by equine herpes virus 3
2. Transmission also occurs by indirect contact and inhalation virus droplets
3. Incubation period 5-7 days
4. not v common
34
Coital exanthema
| epidemiology and immunity
* Epidemiologically only significant in breeding animals when breeding
* Once infected - solid immunity: most horses are only infected once
35
Clinical signs of Coital exanthema
* Rapidly developing ulcers and papules (1-5mm) on henitalia penis, vulva and perineum
* Lesions can be mildly pruritic but are not painful
* Healing of lesions may leave permanently depigmented spots on the skin
36
Diagnosis and treatment Coital exanthema
• Clinical signs
• Virus isolation difficult
• Not very common disease
Treatment:
• Stop breeding (i.e. stallion or mare servicing) until at least 3 weeks after the lesions and ulcers have healed
• Topical antimicrobials / antiseptics (stop infection)
• Local anaesthetic creams (stop itchiness/pruritic) if necessary
37
Horse POX
Common?
2 Different forms?
Signs and treatment
```
VIRAL
V rare
2 forms:
o Buccal form (just around mouth) -corner of lips and nostril
o Cutaneous form (whole body)
```
* Mild systemic signs: fever and depression
* No treatment: spontaneous regression – few days
38
Papular dermatosis
Viral
• Very rare (Africa, USA)
• Unspecified Pox virus
• Annular papular lesions, non-pruritic or painful
• Most cases resolve in 4-6 weeks: no need for specific treatment
• Just be aware it exists
39
Sarcoid
1. most common skin tumour in horses
2. Tumour of fibroblasts of the skin
3. Potential association with Bovine Papillomavirus 1 and 2
40
Are sarcoids a viral disease?
• Not viral disease but parts of Genetic material for papillomavirus can act as an oncogene which gets inserted in fibroblast DNA transformed normal F into tumour sarcoid
41
any predisposition to sarcoids?
| Location associated with
• No sex or breed predisposition
| Location - NEAR BLOOD SUPPLY
42
NAme the different clinical presentations of sarcoids
1. Occult sarcoid
2. Verrucose sarcoid
3. nodular sarcoid
4. Fibroblastic sarcoid
5. mixed sarcoid
6. Malignant sarcoid
43
Describe
1. Occult sarcoid
2. Verrucose sarcoid
3. nodular sarcoid
OS – area where hair looks a bit different, alopecia, looks similar to ringworm with hair, ventral abdomen and NEAR blood vessel (as shown on pic) helps to determine sarcoid not ring
VS – looks like wart, cauliflower
NS – looks like a solid mass, cutaneous
44
Describe
4. Fibroblastic sarcoid
5. mixed sarcoid
6. Malignant sarcoid
FS – fleshy looking lesion, ulcerated
MS – more than one form of sarcoid, this pic got VS, FS and OC in middle where skin looks different
Maglignant S – not actually malignant, just very aggressice locally, can cause lot of damage to skin in area
45
Diagnosis sarcoid
Biopsy
• Histologically distinctive
• Dangers of exacerbation – fibroblasts arrive at site of injury – taking a biopsy will lead to more fibroblasts arriving.
• Be ready to treat if positive diagnosis needs treating before biopsy makes it worse.
• Only interfere if able to treat quickly after
46
Treatment sarcoids
- long list = nothing 100% perfect
• Surgery / Cryo / Laser
• ‘Immune’ therapy – sarcoid tumours are ignored by the immune system – we need to make the tumour recognisable by the immune system:
o BCG Injections – allows tumour to be recognised by immune cells.
o Vaccines
• Cytotoxics (topical & injection)
• Antimitotics (topical)
• Photodynamic therapy – inject substance that will get excited at specific wavelength and destroy sarcoid cells
• Radiation (very expensive/lots of paperwork/risk to us)
• Homeopathy / Natural medicine
NB the more treatments you try, and fail, the more difficult the sarcoid will be to treat.
47
Sarcoid prognosis: rules you must follow when dealing with sarcoids
RULE 1:
• The more they have the more they get
RULE 2:
• The fewer they have the fewer they get
RULE 3:
• Multiply over summer (flies more active in summer) & grow over winter (become apparent)
RULE 4:
• A single sarcoid implies (genetic) susceptibility
o This remains for life!
o Treat and all go away – doesn’t mean will never get them again
