derm Flashcards
Ehlers danos syndrome
group of genetically heterogenous connective tissue disorders linked with genetic defects affecting collagen or other extracellular matrix proteins
Hereditary equine regional dermal asthenia (HERDA) is seen in what breed
American quarter horses
Hereditary equine regional dermal asthenia (HERDA) gene mutation
PPIB: peptidyl prolyl isomerase B gene
** acts as a chaperone involved in proper folding of collagens
Hereditary equine regional dermal asthenia (HERDA) C/S
usually seen at 2 years old when broken into saddle– skin tears, or wounds with prolonged healing times
**develop disfiguring scars
-skin is loose and hyperelastic
What is the prevalence of Hereditary equine regional dermal asthenia (HERDA) in
Quarter horses?
3.5%
**inc prevalence in cutting horses (up to 28%)
**w/in pleasure/working-cow horses (up to 12.8%)
Warmblood fragile foal syndrome gene mutation
PLOD1 (procollagen lysin, 2-oxglutarate 5- dioxygenase 1) gene
**codes enzyme for collagen biosynthesis
Warmblood fragile foal syndrome C/S
is af atal defect of connective tissue involving severe skin malformations in enonatal foals
Chronic progressive lymphadema is seen in what breeds?
draft breeds: clydesdales, belgian drafts and shires
chronic progressive lymphadema lesions
start at early age
-progressive swelling of legs & development of severe chronic skin changes such as hyperkeratosis & dermal fibrosis with thick skin folds & nodules
-secondary skin infections– contrib to chronic changes
-severe discomfort
Junctional epidermalysis bullosa gene mutations
- LAMA 3: american saddlebreds
- lamC3– belgian and other drafts
Junctional epidermalysis bullosa clinical signs
mechanobullous dz: development of ulcers adn bilsters in the skin at pressure points (hocks/stifle) or mucocutaneous junctions (mouth & anus)
oral lesions: premature eruption of teeth & loss of enamel= bleeding mouth
Hypotrichosis is a disease of what breeds?
curly coated breeds: american bashkir, culry horses and missouri fox trotters
hypotrichosis clinical signs
alopecia @ birth or develops early during neonatal period
defects in ectodermal structures: teeth, hooves, eyes or seat glands
– normal shedding periods, some permanent loss of main & tail
Pemphigous foliaceus describes a group of what disorders?
autoimmune vesiculobullous disorders characterized histologically by:
-intraepidermal acantholysis
-intercellular deposition of immunoglobulin
What are the clinical lesions primarily recognized in Pemphigous foliaceus?
-scaling
-crusting
–>generalized exfoliative dermatitis, ventral or peripheral edema, fever depression
What are characteristic histologic findings of Pemphigus foliaceus?
-intragranular to subcorneal cleft and vesicle formation assoc with acantholysis
Why is recommended to review on slide exam of biopsies in cases of pemphigus foliaceus?
certain strains of Trichophyton spp of dermatophytes may also cause acantholysis
**any histology suggestive of pemphigus foliaceus must be stained for fungi
What are recommended treatments for pemphigus foliaceus?
-immunosuppressive doses of corticosteroids
-prednisolone: 1 mg/kg
-dexamethasone: 0.08-0.1 mg/kg PO q24h, then tapering
-gold salts (historic tx)
-azathioprine: 1-3 mg/kgPO q24-48h
Why is oral prednisole preferred to prednisone?
–some horses are unable to metabolize prednisone into active metabolite of prednisolone
What is the prognosis for horses diagnosed with pemphigus foliaceus?
–lifelong administration of steroids required
Pemphigus vulgaris is a rare autoimmune skin disease ancedotally reported in horses characterized by:
-circulating IgG directed against the epidermal transmembrane protein desmolgein-3
What are clinical signs of pemphigus vulgaris?
vesicles
ulcerations– @ mucocutaneous & cutaneous areas
What is bullous pemphigoid?
an autoimmune vesiculobullous and ulcerative disorder that affects the cutaneous basement membrane zone (BMZ)
What is the pathophysiology of bullous pemphigoid?
complement activaitng anti-BMZ antibodies bind to glycoprotein ag in lamina lucida of BMZ
–collagen activation results in degranulation of mast cells & chemotaxis of neuts &eos
-eosinphils release tissue destructive enzymes with resultant injury to the BMZ, loss of demoepidermal adherence & blister formation