Dermatitis 3 Flashcards
What are the main causes of developmental anomalies?
Genetic defect
In utero infection
In utero exposure to teratogens
What do you call the condition of having less than the normal amount of hair?
Hypotrichosis
What is Singy calf?
Calf with hypotrichosis
Due to in utero BVD infection
What is collagen dysplasia?
Differently sized, and arranged collagen fibers => Hyperdistensful skin
Can easily tear and cause secondary infection
Condition where integument hasnt formed in a select area
Epitheliogenesis imperfecta
-> eg lacking hoof/dermis => secondary bacterial infection
What is the condition where the stratum corneum of the animal is thickened because it is not shed properly. Thickened skin becomes harder and will fisssure and crack
Ichthyosis
Disorders of alopecia can be due to what conditions?
Endocrine disorders Hair cycle abnormalities Excessive grooming Self trauma Autoimmune Poor nutrition Hyperkeratosis Cicatrical alopecia (scar)
What endocrine disordrers can lead to alopecia?
Hypothyroidism
Hyperadrenocortism
Hyperestrogenism
Alopecia X
What hair cycle abnormalities can lead to aoplica?
Post clipping
Telegenic effluvium
Antimitotic drugs- chemotherapeutic/ immunosuppressants
What is feline psychogenic alopecia?
Excessive grooming causing hair loss
Symmetrical alopecia and hyperpigmentation is most likely due to ???
Endocrine disorder
____________ is increased thickness of stratum basale and spinosum
Acanthosis
___________ is increased thickness of stratum corneum
Hyperkeratosis
What is parakeratotic?
Nuclei retained
What is orthokeratotic?
Anuclear
What are the two forms of hyperkeratosis??
Dry form (seborrhea sicca)-> dry skin and white to gray scales that exfoliate
Greasy form (seborrhea oleosa)-> excessive brown to yellow lipids
What re the causes of hyperkeratosis s?
Primary idiopathic seborrhea
Secondary seborrhea
-endocrine imbalances -> hyperadrenocorticism, hypothyroidism, and hyperestrogenism
-chronic dermatitis -> allergy and ectoparasite
Zinc responsive dermatosis
Who is predisposed to primary idopathic seborrhea?
Cockers, Springers, and Westies
What is primary idiopathic seborrhea?
Inherited disorder of keratinization or cornification
-involve hyperproliferation of epidermis, hair follicle, and sebaceous glands
Who is predisposed to zinc responsive dermatosis ?
Arctic breeds - inherited defect in zinc absorption
Pigs and rapidly growing large dog breeds on low zinc diet
What is the pathogenesis of sarcoptic mange ?
Burrow into stratum corneum -> intense pruritus through hypersensitivity -> self trauma, chronic irritation -> hyperkeratosis, lichenification, alopecia
What is a raised, irregular patch of thickened skin developing from chronic friction, usually over pressure points
Callus
What is a cutaneous soft tissue sarcoma?
Spindle cell tumor
Very common in dogs
What are the types of soft tissue sarcomas?
Fibrosarcoma Nerve sheath tumor Malignant fibrous histiocytoma Liposarcoma Myxosarcoma
Cattle
Horny, cauliflower like masses
What is this most likely?
Papilloma
What is the pathogenesis of papilloma virus?
Viral genes inactivate host tumor suppressor proteins
In horse
Nodular to plaque-like elevations
Histology shows both dermal and epidermal components
Equine sarcoidosis
T/F: Equine sarcoidosis are highly invasive and metastatic
F
Highly invasive and have a high rate of recurrence
DO NOT metastasize
What are equine sarcoids caused by?
Bovine papilloma virus
Verrucous and ulcerated lesions in a poorly pigmented, sparkly haired area
Histology shows keratizing squamous cells
Squamous cell carcinoma
What is a benign growth of dogs that are grossly white-yellow, greasy, and cauliflower like
Sebaceous adenoma
What is a fatty benign growth of dogs?
Lipoma
T/F: In cats and dogs, mast cell tumors are always considered malignant, but in horses are considered benign.
F
Dogs= malignant
Cat and horse = benign
What stain can you use to visualize a mast cell tumor?
Toluidine blue
Histiocytoma most commonly affects who?
Dogs, mostly young, but can be of any age
What is a histiocytoma?
Benign tumor
Langerhans cell organ
Grossly: dome-shaped
Cyto: round cells
Who usually gets melanomas?
Dog
Horse
Angora goat (not just any old goat)
In a canine, melamomas that are oral, or mucoctuatous are often (benign/malignant), but ones in haired skin are usually (benign/malignant)
Malignant; benign
I have a gray horse with a darkly pigmented mass around the perianal area. What is at the top of my DDX?
Melanoma
- usually progressive and multicenteric
What is hemangioma caused by?
Solar radiation
- metastatic potential may vary with depth of tissue invasion
What are the two types of cutaneous lymphoma?
Epitheliotropic
-Tcells
Nonepithelotropic
-T or B cells
What are factors that influence melanin production?
Hormone
Gene
Age
Inflammation
What is hyperpigmentation
AKA hypermelanosis
Usually increase in amount of melanin rather than number of melanocytes
Generalized hyperpigmentation can be caused by?
Endocrine dermatosis (Cushing, hypothyroidism, hyperestrogenism)
Acanthosis nigricans- genetically determined disease of young dachshunds
What causes localized hyperpigmentation ?
Chronic inflammation or physical irritation (rubbing/friction)
Congenital (freckles)
Dog with localized hyperpigmentation on its back near the base of tail. What should be at the top of your DDX ?
Chronic flea allergy dermatitis
What are the congenital causes of hypopigmentation?
Inherited lack of melanocytes
Piebaldism -foci with lack of melanocytes
Albinism - melanocytes are present but defect to synthesize melanin (usually tyrosinase gene)
What are acquired causes of hypopigmentation?
Copper deficiency
Destruction of melanocytes or melanin-containing keratinocytes (pigmentary incontinence) -> autoimmune
What is the MDx for lack of pigment?
Leukoderma
Foal that is albino and has died of colic has what genetic defec?
Lethal white syndrome
Colonic hypoplasia and leukoderma
-> lack of melanocytes and cells from the myenteric plexus
How does copper deficiency lead to lack of pigmentation?
Copper is an important cofactors for tyrosinase
-> lack of tyrosinase function -> decreased melanin production
What is Arabian Fading Syndrome? How does it appear?
Vitiligo= Idiopathic acquired melanocytopenic hypomelanosis
Gradually expanding pale macules, often symmetrical
What is vitiligo
Lack of melanocytes (idopathic acquired)
What is the most commonly type of calcification found in the skin?
Dystrophic
- calcinosis cutis
- calcinosis circumscripta
Dog with hyperadrenocortisim has erythematous to white gritty plaques and nodules on the skin
What is this ?
Calcinosis cutis
Single hard subcutaneous nodules over a pressur point or previous site of trauma/injection
Calcinosis circumscripta
Dog:
Mild granulomatous inflammation around a deposit of calcium in the dermal and subcutaneous CT
Calcinosis circumscripta
Thickened/puffy gelatinous skin, sometimes with viscous fluid exudate
Mucins is
Who gets mucinosis?
Chinese Shar-Pei (inherited)
Myxedema with hypothyroidism
