Introduction to equine derm Flashcards
Describe type 1 hypersensitivity - give horse example
IgE mediated involving the release of histamine by mast cell.
e.g. Insect-bite hypersensitivity AKA Sweet itch
Describe type 2 hypersensitivity - give a horse example
IgG mediated cytotoxic response associated with complement binding.
e.g. Pemphigus complex
Describe type 3 hypersensitivity- give a horse example
Immunocomplex deposition on endothelial beds
e.g. Pastern leukocytoclastic vasculitis, purpura haemorrhagica, Lupus..
Describe type 4 hypersensitivty- give a horse example
T- cell mediated.
e.g. Insect-bite, drug eruptions
if skin lesions are on mane, tail and ventral line what is a likely cause
insect-bite hypersensitivity
if skin lesions are on base of tail- list 3 possible causes
Oxyuris equi AKA pinworm
Insect-bite hypersensitivity
Lice infestation (normally more truncal)
If skin lesion on group, chest, neck and sometimes face- name a possible cause
fungal infection
If skin lesions affect back, chest, rump and sometimes face- what is a likely cause
rain scald
if skin lesions affect distal limbs- list 2 possible causes
“Mud fever” : bacterial ± fungal
Mite infestation: Trombiculiasis, chorioptic mange
If skin lesion affects truncal, neck and occasional head- list 3 possible causes
urticarias
atopia
lice infestation
If skin lesions affect back and girth area- list 2 possible causes
contact dermatitis
fungal infection s
List 10 skin lesions that are defined as primary
macule
patch
papule
plaque
vesicle
pustule
wheal
nodule
tumour
abscess
List 7 skin lesions that we define as secondary lesions
alopecia
scale
crust
erosion
ulcer
lichenification
hypo/hyperpigmentation
what are coat brushing good to diagnose
ectoparasites
what can skin scrpaes be used to diagnose
mites
dermatophytes
what are skin biopsies ideal for
nodules and deep pyodermas
culture and histolog
what can acetate tape be used to diagnose
Oxyrus equi eggs
what causes rain scald
Dermatophilus congolensis
what are the 2 types of allergy tests in horses
serum (SAT)- poor sensitivity
intradermal (IDT)- better diagnostic yield
Basically neither of them are very good so not done often
what does hair coat shedding depend on
daylight hours- melatonin and prolactin driven