Skin Lesions Flashcards
What organism is responsible for ring-like lesions of the skin?
trichophyton verrucosum, a spore-forming zoonotic fungus that can live in the environment for a long time due to the protection of the spores.
T/F: you are able to write health certificates for animals with dermatophycosis because this infection is easily cleared.
false. its classified as a transmissable infectious disease. It can be passed from animal to animal, as well as from fomites to animals, so its important that these animals stay away from others during the course of the infection.
Which of the following is FALSE about ringworm in cattle?
A. it occurs in younger, confined animals, but in older animals is extensive d/t probable immune compromise
B. it typically starts on the head and neck
C. it is characterized by grey, scabby areas with no hair
D. the lesions are pruritic
D. the lesions are pruritic
they are not usually itchy
all of the rest of the statements are TRUE of ringworm.
Which of the following is TRUE about ringworm?
A. it is not self-limiting and requires topical treatments for clearance
B. there are no production losses associated with infection
C. treatment entails topical antibiotics such as gentamicin
D. it does not persist in the environment, so there is no need to clean the barn or tools with bleach
B. there are no production losses associated with infection (unless there is underlying disease)
Ringworm IS self-limiting, but you can apply topical treatments. First, you want to scrape off the scabs (dispose of them carefully), wash with gentle soap, wash with 2-4% iodine solution 2x/day for 1-2 weeks, and apply clotrimazole. Note that this has a 24 hr meat WD.
It is recommended that you do clean the barn and tools with 1:4 bleach because this organism persists in the environment due to spore formation
How do you determine if a ringworm lesion is healed?
Bonus for the UNRELIABLE way to determine if its healed
if hair is growing back in the middle of the lesion
unreliable way: free of crusts
Why is DTM media rarely used to diagnose ringworm in production animals?
it can take 3-6 days to show positive.
What are the 3 most common plants that cause primary photosensitization?
- buckwheat
- st johns wort
- smartweed
___________ is ingestion, injection, or absorption through the skin of a photodynamic agent.
primary photosensitization
Describe how a photodynamic agent causes primary photosensitization
high energy molecules react with UV light within the skin and release free radicals
the free radical damage the outer cell membrane and the lysosomal membranes of skin cells which leads to skin ulceration, necrosis, and edema.
T/F: primary photosenitization occurs in healthy cattle on non-pigmented skin, the nose, and the udder.
true
because melanin is what protects from the UV light, therefore lack of melanin does not provide any protection.
What are forages that can cause primary photosensitization?
- legumes
- brassica
How does chlorophyll play a role in primary photosensitization?
if cattle eat dry hay then are turned into lush green pastures, they intake far too much chlorophyll.
The liver is overwhelmed, so the excess chlorophyll turns into phylloerythrin by microorgnisms in the GIT and causes photosensitization in the skin.
You are treating a few holsteins that have primary photosensitization. What is your plan?
- stop their intake of the plants/forage/lush grass
- provide them shade
- prevent secondary infections and provide pain relief (banamine or meloxicam + excede)
___________ is associated with inherited abberrant pigment metabolism which affects both unpigmented and pigmented skin.
type II photosensitization (congenital erythropoietic porphyria and bovine erythropoiteic protoporphyria)
You are called to a farm to investigate the cause of an ill holstein.
On exam, you note this cow has icteric membranes and lesions with hair loss along the white colored hair , as well as some of the black patches. You diagnose this patient with secondary photosensitization.
What caused this condition to occur?
this cow must have had impaired hepatobiliary secretion.
This could be due to many things:
1. a bile duct occlusion (ex. flukes)
2. hepatic dysfunction due to toxins (pyrrolizidine alkaloids in senecia or crotolaria; blue green algae)
3. hepatic dysfunction due to infections
how can you PREVENT photosensitization from occuring?
- provide appropriate quantities of forage and feed
- improve pasture and limit weeds or access to them
- provide shade
Which of the following statements is FALSE about bovine ulcerative mammilitis?
A. treatment includes debriding necrotic teat tissue and likely culling her due to inability to produce milk.
B. it causes decreased milk production and increased incidence of mastitis
C. it causes painful edematous, ulcerated lesions or vesicles that rupture on the udder
D. it can be associated with cold weather
E. cows with this condition should be milked last
A. treatment includes debriding necrotic teat tissue and likely culling her due to inability to produce milk.
Treatment includes iodophore teat dips with emollients and isolation of the affected cows. You must milk these cows last or use separate equipment.
But debridement/removal of tissue is NOT necessary and she will likely heal and be able to produce milk in the near future.
Which of the following statements is MOST correct about pseudocowpox?
A. it is also known as contagious ecthyma
B. infected animals develop life-long immunity and dont typically become reinfected
C. this infection is zoonotic and can produce painful scabs on human hands/arms
D. lesions persist short-term (1-2 weeks), heal as the virus becomes latent, and then lesions reappear several months later
C. this infection is zoonotic and can produce painful scabs on human hands/arms
Pseudocowpox is a parapoxvirus that is RELATED to contagious ecthyma, not equivalent to.
The virus creates small red papules to vesicles/pustules. Small scabs will form around the granulation tissue.
Lesions will persist for several MONTHS. Animals have SHORT immunity so reinfection is possible.
This condition is zoonotic, so humans should wear gloves when milking.
What virus causes bovine warts?
papillomavirus
You are called to a dairy farm because this farmers cows have small, raised, non-painful lesions on their teats. You examine these lesions and they are filamentous/frond-like.
You diagnose this patient with bovine warts (papillomavirus).
Why might they require excision?
because if they are larger or on teat end, they can interfere with milking.
They are also contagious and can be transmitted directly or indirectly (fomites).
Describe the following scores for the stages of teat hyperkeratosis:
A. Stage 1
B. Stage 2
C. Stage 3
D. Stage 4
A. Stage 1 – normal teat end with NO ring around teat canal
B. Stage 2 – smooth raised ring or slightly rough ring with no keratin fronds.
C. Stage 3 – raised, rough ring with isolated fronds of old keratin extending 1-3 mm from the orifice. There is some breakdown of epithelial integrity
D. Stage 4 – raised ring with rough fronds of old keratin extending >4 mm from the orifice. The ring is rough and cracked giving the teat end a flowered appearance.
Why are higher stages (3 and 4) of teat hyperkeratosis concerning?
these stages increase the risk of developing intra-mammary infections such as mastitis
this is because the teat end cannot form a seal and the crusts that develop have the potential to wick staph and other bacteria into the teat end.
Which of the following is NOT a risk factor for teat-end hyperkeratosis?
A. long, pointy teats
B. younger cows
C. later lactation
D. longer milking times (high production, slow milkers)
E. genetics
F. higher vacuum machine
G. more movement in the liner of the milking machine
H. higher frequency of milking
B. younger cows
older cows are at more of a risk
What is the prevention for teat-end hyperkeratosis?
- ensure proper milk let down (appropriate milk timing and appropriate claw attachment)
- adjust automatic take offs
- teat cleansing and post-dips with emollients
