Approach to alopecia 2 Flashcards
What is the pathogenesis of non-inflammatory spontaneous alopecia?
When there is a problem with stimulators or formation of hair itself
What are the non-inflammatory conditions of hair follicle arrest?
*Endocrinopathies
*Alopecia X
*Telogen defluxion
*Paraneoplastic alopecia
*Cyclical flank alopecia
*Post-clipping alopecia
*Injection alopecia
What are non inflammatory conditions of hair synthesis defects?
*Congenital alopecia
*Pattern alopecia
*Follicular dysplasia
*CDA / BHFD
*Anagen defluxion / effluvium
*Sebaceous adenitis
What are the 3 phases of hair cycle?
*Anagen
*Catagen
*Telogen
What is anagen?
Growing phase of hair
What is catagen?
Transition phase with regression of the lower part of the hair follicle
What is the telogen phase?
*Quiescent / resting phase
What hormone promotes hair growth?
Thyroid hormone
What hormones suppress hair growth?
Oestrogen
Glucocorticoids
What are the clinical features of endocrinopathies leading to alopecia?
*Symmetrical to generalised alopecia - bilateral alopecia (inside out)
*Dull and dry coat (lack of thyroid)
*Scaling
*Comedones
*Hyperpigmentation
*Atrophic skin
*Poor wound healing
*Post-clipping alopecia
What causes atrophic skin?
Cushings - hyperadrenocorticism = thinning of epidermis = vessels seen through skin
What does cushings do considering hair growth?
Blockade of telogen to anogen (stop hair growth)
What does hyperadrenocorticism cause?
*Truncal alopecia
*Comedones - black head
*Skin atrophy and striae (wrinkles)
*Prominent blood vessels
*Calcinosis cutis - calcium build up
*Cats – fragile skin
What does calcinosis cutis start as? Where is it located?
*Start as small dorsal neck
*Seen on dorsal neck
What does hypothyroidism cause?
*Truncal and extremity alopecia
*Myxoedema ‘tragic’ facial expression
*Weight gain
*Lethargy
*Heat seeking
What does hyperestrogenism cause?
Promotes decreased hair growth
What can sertoli cell tumour cause?
Hyperpigmentation of genital area
Hyperestrogenism = feminisation + decreased hair growth
What is telogen defluxion?
*Sudden loss of hair
*Occurs 1-3 months post stress incident
-pregnancy, lactation
-severe illness
-shock , surgery
*Shed as new hair develop
What is anagen defluxion?
*Sudden hair loss
-chemotherapy
-severe illness
*Damage to growing hair/follicle
*Patchy to complete hair loss
*loss of whiskers
What can cause feline paraneoplastic alopecia?
*Pancreatic + bile duct carcinomas
What is alopecia X?
Alopecia of unknown cause
What is the rule with recurrent flank alopecia?
*More it occurs less chance of hair growing back
*Seasonal + restricted to flanks
What is a concern with congenital alopecia + hairless breeds?
Hair follicles can get blocked - can lead to bacterial infection
what can be done with pattern alopecia?
Nothing can be done - owners will be concerned
What occurs with follicular dysplasia?
Abnormal hair in hair follicles keep falling out
Progressive hair loss
What occurs with black hair follicle dysplasia?
*Black hairs don’t form properly - v friable + fracture easily
*More they fracture = more they fall out
What does colour dilution alopecia cause?
*Dilute colour coats - blue / fawn
*Macromelanosomes - melanin clumping = hair fragility
=hair loss + scaling
How do you treat hair synthesis defects?
*Avoid damage to coat
*High quality nutrition
*Gentle anti scaling shampoos
*Prevent / treat secondary bacterial infections
*Protect from sun
