Small Ani. Med- Canine Symmetrical - bilateral alopecia 2 (Lecture 8)

drraythe's version from 2016-04-29 14:39

Follicular dysplasias (FD)

Question Answer
what are three disorders which are considered follicular dysplasias?Color dilution alopecia, Pattern alopecia/baldness, Canine recurrent (flank) alopecia
what are Follicular dysplasias?Genetic/hereditary diseases characterized by abnormality of hairs and hair growth. They are breed specific.
do follicular dysplasias have breed predilections?Breed specific
typical age at which follicular dysplasias happen?Juvenile to young adult animals
what two things should you microscopically examine with follicular dysplasias?hair and follicular dysplasia
what are the only 2 diagnostic tools to dx follicular dysplasias?Skin biopsy and histopathology is the only diagnostic tool
what should you warn owners about treatments of follicular dysplasias?No 100% effective therapy is reported
Color dilution alopecia aka color linked follicular dysplasia--> how do dogs get this? What exactly is going on with this dz?Genetic/hereditary disease. Defect in melanin transfer leading to follicular dysplasia, hair dysplasia and alopecia
Color dilution alopecia--> this is a genetic dz-- what is mutated to cause these problems?A mutation in the protein melanophilin has been identified in diluted dogs at the “d” locus for dilution
Color dilution alopecia--> what is actually causing the follicle dysplasia?The accumulation (clumping) of melanin probably is the cause of the follicle dysplasia (Loss of integrity of hair shaft leads to increased breakage)
which dogs are more prone to getting color dilution alopecia?Diluted dogs (blue/gray/fawn), so: Doberman pinscher, Yorkshire terrier, Saluki, “Silver lab”
age of onset for color dilution alopecia?3 months - 1 year
what are the lesions/clinical signs of color dilution alopecia?Progressive alopecia that affects all diluted areas. Alopecia, scales; papules and pustules with secondary bacterial folliculitis (common)
how do you dx color dilution alopecia?History (color, age), Distribution of the alopecia, Trichoscopy, Skin biopsy
what would you see on trichoscopy which would make you suspect color dilution alopecia?clumping of melanin (not being distributed properly)
what will histopath of color dilution alopecia look like?melanin clumping in cells of hair follicles
how do you treat color dilution alopecia?Control of recurrent secondary pyoderma, Regular topical therapy is useful. There is NO CURE
Pattern alopecia (pattern baldness)--> what is the cause of this?unknown (suspected genetic disease)
age of onset for Pattern alopecia (pattern baldness)?6 months - 1 year
are there breed predilections for pattern alopecia?Dachshund, Chihuahua, Greyhound, Boston Terrier
what is distribution like for pattern alopecia?Progressive alopecia of ear flaps, post-auricular region, ventral neck and thorax, caudo-medial thighs
how do you dx pattern alopecia?rule out endocrine skin diseases, skin biopsy
how do you tx pattern alopecia?there is no tx
Canine recurrent alopecia---> 2 akas?Cyclic flank alopecia, Recurrent flank alopecia
cause of canine recurrent alopecia?unknown; suspected a dysregulation of the hair cycle due different photoperiod
is there breed disposition for canine recurrent alopecia? (cyclic flank alopecia)Airedale terriers, Boxers, Bulldogs predisposed
is there an age disposition for canine recurrent alopecia? Sex? (cyclic flank alopecia)Young adults, males and females
is canine recurrent alopecia seasonal?Spring or autumn in the northern hemisphere (they think its a dysregulation of the hair cycle due different photoperiod so yes, seasonal)
what is the distribution of the alopecia in the canine recurrent alopecia? What is the quality of them like?symmetric bilateral flank alopecia, Alopecic areas are well demarcated (“geographic”) and hyperpigmented
how do you dx Canine recurrent flank alopecia?History, clinical picture, Rule out endocrine diseases, Biopsy + histopathology
how do you tx Canine recurrent flank alopecia? (2)(1) Benign neglect (2) Melatonin (3-6mg/dog PO, BID, start at least 1 month before the onset of alopecia)
Diagnostic plan of canine symmetric alopecia--> the 7 steps to figure out what it is(1) Signalment, history (age), clinical signs (distribution of the lesions) --> (2) Presence of systemic signs? --> (3) Rule out other causes of folliculitis (Skin scrapings, trichoscopy, cytology) --> (4) CBC, biochemistry profile, urinalysis --> (5) Thyroid panel --> (6) +/- Adrenal function tests and adrenal ultrasound --> (7) Skin biopsy + histopathology