Crusting and scaling Flashcards
Define scale
an accumulation of loose cornified fragments of the stratum corneum
Define crust. Cause?
presence of a dried exudate on the skin surface. Due to epidermal inflammation: severe oedematous response OR marked cellular recruitment.
3 common triggers: physical damage, infection, infestation
Define seborrhoea
= flow of sebum. Vague clinical term for scaling/greasy exudation
Define seborrhoea sicca
dry scaling
Define seborrhoea oleosa
oily scaling
Define seborrhoea dermatitis
greasy, inflammed skin
What are the 2 main causes of scaling and crusting
Defects of keratinisation/cornificiation (use depends on vet). It refers to skin disease where scaling/follicular casting is a dominant clinical feature.
SECONDARY to: parasites, infection, nutritional, allergy, neoplasia.
PRIMARY: idiopathic, genetic defect
What is spaniel seborrhoea?
Dx
Tx
- a primary defect in cocker spaniels
- increased mitotic rate/turnover time
- skin grafts remain hyperproliferative
- Dx - to exclude primary causes, biopsy
- Tx - shampoo, vitA, retinoids
What is sebaceous adenitis?
Dx
Tx
- affects various breeds (St poodle, Akita)
- sebaceous glands destroyed
- Dx - exclude primary causes, biopsy
- Tx - shampoo, EFA, cyA, (retinoids)
What are the problems with administering retinoids?
- teratogenic
- dry eye
List Ddx for pruritic, steroid-resistant crusting lesions
- scabies
- (pemphigus)
- (dermatophytosis)
- (cutaneous lymphoma)
What should you do if you suspect sarcoptic mange but don’t find it on the skin scrape?
Treat anyway (to avoid severe progression of disease if you didn’t detect it)
How can scabies be treated? 4
- Amitraz (licensed of canine scabies) - weekly for 6 w
- body clip (to reduce amount of hair)
- Prednisolone (to reduce itch)
- Cephalexin (an AB to reduce secondary bacterial infection due to the excoriation
- Others: selamectin (stronghold/revolution), imidacloprid/ moxidectin (Advocate)
Name 3 typical lesions of scabies
pruritus, papules and crusts
T/F: scabies is often refractory to steroids
True
T/F 3 weekly treatments may not be enough to treat scabies, especially in long coated breeds
True
T/F: ivermectin is contraindicated in the treatment of scabies in collies
True
Define dermatosis
a disease of the skin, especially one that does not cause inflammation.
Define SND
Superficial Necrolytic Dermatitis
SYNONYMS = diabetic dermatosis, hepatocutaneous syndrome, metabolic epidermal necrosis, necrolytic migratory erythema.
Describe SND lesions
Uncommon erosive, crusting, ulcerative disease which commonly affects the footpads, extremities and peiorificial skin of middle-aged and old dogs.
When is SND seen?
with hepatic diseases (cirrhoisis, vacuolar degeneration) or pancreatic glucagonoma. Poor prognosis? reverse hepatic disease.
List ddx for pruritic disease in heifers
- ectoparasite infestation
- dermatophytosis (ringworm in calves)
- dermatophilosis (mud fever, crusting lesion)
- nutritional abnormality
- inherited keratinisation defect
Define parakeratosis
= a mode of keratinisation characterised by the retention of nuclei in the stratum corneum. In the MM this is normal. In skin, this leads to abnormal replacement of annular sqaumes with nucleated cells.
Define orthokeratosis
the formation of an anuclear keratin layer, as in the normal epidermis
Define hypotrichosis
a condition of abnormal hair patterns - predominantly loss or reduction of hair
