Alopecia Flashcards
What are the three stages of the hair growth cycle and what occurs in each of them?
Anagen = active growth
Catagen = involution of the hair shaft
Telogen = no growth
Where are the keratinocytes that form hair shafts?
Situated at the matrix of the hair bulb
What are the two processes that allow for hair growth?
Epidermopoiesis and keratogenesis
Describe the three main pathogenic mechanisms that result in alopecia.
Destruction or distortion of normally growing hair follicles and hair shafts.
Abnormalities of the hair cycle causing atrophy of hari follicles and regression of hair growth.
Abnormalities of hair follicle and hair shaft development causing structural defects, hair fragility and failure of normal growth of hair.
List three causes of the destruction or distortion of normally growing hair follicles and hair shafts.
Traumatic alopecia, folliculitis and inflammatory alopecia
What would cause abnormalities of the hair cycle causing atrophy of hari follicles and regression of hair growth?
Endocrinopathies
What must occur initially for dermatophytosis?
Adherence between keratinocytes and arthrospores.
What is the incubation period of dermatophytes?
1 to 3 weeks
List three dermatophytes that are associated with infections?
Microsporum canis
Trichophyton
Microsporum gypseum
List three clinical signs of dermatophytes.
Alopecia
Scale
Folliculitis and furunculosis
Which media would you use for fungal culture of dermatophytes?
Sabouraud’s media
Describe how you would perform Wood’s Lamp technique for diagnosis of dermatophytes.
Lamp should be warmed up for five minutes.
Animal should be examined in a darkened room for several minutes to allow lesions to fluoresce.
What is Wood’s lamp technique useful for?
Useful for M. canis isolates ONLY
How far may infection spread from obvious lesions of dermatophytes?
Up to 6cm away
Which shampoo and which dip/rinse can you use as topical therapy for dermatophyte infection? How often should you use them?
Shampoo - malaseb
Dip/rinse - enilconazole (imaverol)
Twice weekly and left of for 10 minutes
List the two medications that you can use for systemic therapy for dermatophytes.
Itraconazole (7 days x 3 with 7 days between each)
Ketoconazole
Which dermatophyte usually causes equine dermatophytosis?
Trichophyton spp.
Whivh horses are usually affected by equine dermatophytosis?
Young horses
What topical therapy can you use for equine dermatophytosis?
Miconazole shampoo
Enilconazole
List three methods of diagnosing demodex
Deep skin scrapings
Hair plucks
Skin biopsy
List three factors that would consititute generalised demodicosis
More than five lesions
One major body region affected
Two or more feet
How would you treat demodex?
Moxidectin
Isoxazolines - afoxolaner, fluralaner, lotilaner, sarolaner
How would you treat bacterial pyoderma associated with demodex?
Bathe with chlorhexidine-based shampoo three times a week.
Oral cefalexin 30 mg/kg bid for 4-12 weeks if there is no response to topical therapy or if deep infection is present
Which breed of dog has congenital hair follicle dysplasia?
Chinese crested dogs
How would you diagnose hair follicle dysplasia?
Histopathology
Rule out endocrine disease
