Farm Animal Dermatology Flashcards
What are the possible diagnostics available when it comes to dermatology?
- Skin scrapes
- Sticky tape
- Skin biopsy: including the edge of the lesion for both normal and abnormal histopathological comparison
- Whole lesion removal
When considering treatment for dermatological cases in farm animals, what must be considered?
1) Most chronic skin disease have a secondary bacterial dermatitis and therefore antibiotics are likely needed
2) Meat and milk withdrawals must be considered
3) The use of steroids in pregnant animals is contraindicated
4) Topical treatments are not practical on a herd/flock basis
What are the common and uncommon skin diseases of cattle?
Common:
- Besnoitia besnoiti
- Ectoparasites: Sarcoptic, Psoroptic, Chorioptes, Lice
- Photosensitization
- Ringworm
- Vitamin and trace element deficiencies/ toxicities
- Anagen Defluxion: stress-induced
- Genetic Skin Diseases: Follicular Dysplasia or Epitheliogenesis Imperfecta
- Immunological: Type 1 Hypersensitivity
- Cellulitis
- Cutaneous Actinobacillus
- Actinomycosis = Lumpy Jaw
- Bovine Papillomatosis
- Eosinophilic Granuloma
- Melanoma
- Toxic Gangrenous Mastitis
- Urticaria: Hives
Uncommon:
- Ergotism
- Cutaneous lymphoma
- Squamous Cell Carcinoma
- Type 2, 3, and 4 Hypersensitivities
What are the common skin diseases of sheep?
Common:
- Cobalt Deficiency
- Seasonal Allergic Dermatitis: hypersensitivity to Cullicoides bites
- Photosensitization
- Ringworm
- Psoroptes ovis = sheep scab
Besnoitia besnoiti is an ___________
Obligate intracellular protozoan parasite
How is Besnoitia Besnoiti transmitted?
- Still 100% unknown, but experimentally can be transmitted mechanically through blood-sucking insects
There are 2 distinct sequential clinical stages to the Besnoitia Besnoiti infection, what are they?
Acute Stage:
- Pyrexia
- Subcutaneous oedema
- Swollen Joints: limping
- Conjunctivitis + Scleral cysts
- Photophobia
- Respiratory problems: due to pinpoint-sized cysts lining the mucosa
Chronic Stage:
- Skin nodules may be seen on the legs, ears and back
- Skin thickening = “Elephant skin”
- Alopecia
- Hyperpigmentation
- Poor BCS
- Scleral Cysts
Where does Besnoitia Besnoiti reside in chronic infections?
- Dermis
- Subcutis
- Vestibulum of vagina
- Testis
- Muscle
How can Besnoitia Besnoiti be diagnosed?
- White nodules in scleral conjunctiva (even in sub-clinical cases)
- Histology of skin biopsy
- ELISA and IFA for antibodies in serum
- PM: looking for multifocal white pinpoint granular structures (tissue cysts) in the Upper Resp Tract
What is the treatment for Besnoitia Besnoiti?
NO treatment
- Sulfamides to decrease the severity of clinical signs
How can Besnoitia Besnoiti be prevented/ controlled?
- Test all new entries into herd
- Avoid sharing pastures
- Avoid natural mating
- Cull animals with clinical signs
- Bug repellents when animals kept indoors
What are the possible DDx to the Acute stage of Besnoitia Besnoiti?
- IBR
- Photosensitization
- Blue Tongue Virus
- Malignant Catarrhal Fever
- Mycoplasma bovis
What are the possible DDx to the Chronic stage of Besnoitia Besnoiti?
- Photosensitization
- Mange
- Ringworm
- Vitamin or Trace element deficiencies
How can Besnoitia Besnoiti be diagnosed?
- Clinical signs: tissue cysts on scleral conjunctiva and/ or vaginal mucosa + skin thickening
- Skin Biopsies
- Serology: ELISA
What are the types of photosensitization in cattle?
All of these lead to the presence of a photodynamic agent in the skin
- Primary: ingestion of St. Johns Wort, Bishops weed, or Tetracyclines
- Secondary: impairment of liver function causes an accumulation of chlorophyll depositing in the skin
- Tertiary: inherited altered pigment synthesis = Bovine Erythropoietic Protoporphyria, more commonly seen in Limousine cattle
- Idiopathic
What is the treatment for Photosensitization?
- Move indoors/ remove from direct sunlight
- Corticosteroids (NSAIDs if pregnant)
- Antibiotics if secondary infection: Amoxicillin LA
- Treatment for liver fluke if that is the offending cause on the liver
What is Anagen Defluxion and why does it happen?
Widespread loss of hair over the neck, trunk, limbs and head = Baldy Calf Syndrome
Typically this will follow an acute episode of systemic stress/ pyrexia, e.g. calf diarrhea, pneumonia, septicemia leading to extensive hair loss
What is the treatment for Anagen Defluxion?
- Treat the underlying cause of the stress/ fever
- Multivitamin injection may help too