Crusting-Scaling and Pigmentary Disorders Flashcards
is crust usually a primary or secondary lesion?
secondary
rarely primary
when might you see crust as a primary lesion?
skin/epidermis itself becomes a crust due to necrosis- vasculitis, burns
less common: combination still connected to each other and glutted together by sebum
what are the pustular diseases?
pyoderma
pemphigus foliaceus
what diseases are associated with follicular casts?
sebaceous adenitis
demodicosis
dermatophytosis
what happens in sebaceous adenitis?
inflammatory cells attack sebaceous glands, destroy them
what is sebaceous adenitis associated with?
thymoma-associated exfoliative dermatitis- cats
non-thymoma-associated exfoliative dermatitis- cats
leishmaniosis
idiopathic/hereditary
which breeds have an autosomal recessive mode of inheritance of sebaceous adenitis?
akitas
poodles
is there pruritus associated with sebaceous adenitis?
no- unless secondary pyoderma present
when does sebaceous adenitis show up in predisposed breeds?
1-3 years old
how can you confirm diagnosis of sebaceous adenitis in biopsy?
nodular perifollicular dermatitis
mural folliculitis
sebaceous gland absence
how can you treat sebaceous adenitis?
cyclosporine
topical treatment
vitamin A
steroids alone not effective
apoquel +/- steroids?
cosmetic issue mainly
how long is sebaceous adenitis treated?
best clinical response in about 4 months of treatment
usually life-long
what is sebaceous adenitis like in cats?
very rare
can be pruritic
mostly in association with exfoliative dermatitis
what can cause primary cornification disorders?
ichthyosis
Zn-responsive dermatitis
primary seborrhea
what is the goal with management of cornification disorders?
reduce epidermal proliferation and scale formation
enhance desquamation
what are the types of anti-seborrheic medications for cornification disorders?
keratolytic
keratoplastic
what is the mechanism of action of synthetic retinoids?
act in nuclei
bind to nuclear retinol receptor molecules
modify gene transcription
what are the effects of synthetic retinoids?
anti-proliferative
anti-inflammatory
immunomodulatory
what is ichthyosis?
group of inherited skin disorders with symptoms that include dry skin, redness, cracking, scales on skin and commonly foot pads
what are the clinical signs of canine ichthyosis?
early age
hyperkeratosis
+/- secondary infections
not pruritic unless secondary infection
what is the likely cause of golden retriever ichthyosis?
PNPLA1 gene mutation
lipid layer defect
3/15 had clinical signs
how can you definitively diagnose ichthyosis?
skin biopsy
what are some secondary cornification disorders?
allergy and cheyletiellosis
hypothyroidism
leishmaniosis
T-cell lymphoma
what do primary pigmentary disorders affect?
melanocytes/melanin
what can be seen on trichoscopy with color dilution alopecia?
melanin clumping and hair shafts damage
which animals are predisposed to vitiligo?
young animals
which animals are predisposed to lentigo?
young to middle aged animals
how can you distinguish between pigmented papilloma and melanocytoma/melanoma?
both palpable/raised
melanocytoma is usually single and papilloma are usually multiple
where are lesions in uveodermatologic syndrome?
always on face (nose) or head
what are the layers of the epidermis?
stratum corneum
stratum granulosum
stratum spinosum
stratum basale
what does crust occur secondary to?
ruptured pustule/abscess or leaking pus/sebum
with blood secondary to pruritus/self-trauma
what does the skin/epidermis itself become a crust due to?
necrosis- vasculitis, burns
very adherent to skin
what is the crust in sebaceous adenitis and Zn-responsive dermatitis?
thick scales glued together by sebum
what is the etiology of sebaceous adenitis?
sebaceous gland development genetic defect results in glands inflammation
autoimmune theory: organ-specific
cornification defect leading to sebaceous ducts obstruction
lipid metabolism defect leading to cornification defect and abnormal sebum secretion
what are the clinical signs of sebaceous adenitis?
gradual development of follicular casts and spontaneous hypotrichosis/alopecia
no pruritus unless secondary
maybe leukoderma
lesions on pinnae common
what is sebaceous adenitis like in rabbits?
2-7.5 years
partial spontaneous alopecia
exfoliative dermatitis
how can you treat sebaceous adenitis in rabbits?
cyclosporine
triglycerides
what can cause secondary cornification disorders?
allergy
cheyletiellosis
malassezia dermatitis
leishmaniosis
how can you treat cornification disorders?
moisturizing
anti-seborrheic
drying and degreasing
follicle flushing
antipruritic
antimicrobial
antiparasitic
immunomodulatory
what can you use for moisturizing?
oils
propylene glycol
urea
glycerin
lactic acid
which anti-seborrheic drugs are both keratolytic and keratoplastic?
sulfur
salicylic acid
tar: not for cats
selenium sulfide: not for cats
what can you use to dry/degrease in cornification disorders?
benzoyl peroxide
colloidal sulfur
aluminum acetate
selenium sulfide: not cats
tar: not cats
what are the three generations of synthetic retinoids?
isotretinoin
etretinate, acitretin
adapalene, tazarotene
what are the side effects of synthetic retinoids?
KCS
pruritus
GI upset
liver damage
teratogenicity
periosteal calcification
what is presentation like of primary seborrhea?
before 1 year
cocker spaniels and other breeds
cats too
how is ichthyosis classified?
mode of inheritance
type of histological changes
syndromic/non-syndromic
lethality
how can you treat ichthyosis?
life-long
topical moisturizing shampoo/oils
systemic retinoids
do not breed
what are the melanocyte functions in the skin?
pigmentation
inflammation and defense
which pigmentary disorders are more difficult to diagnose?
pigmented papilloma or melanocytoma
T-cell lymphoma
DLE
leishmaniosis
discoid lupus many differentials
