Exam 3: Congenital and hereditary diseases

definition of congenital diseases

• present at birth regardless of cause

• may be genetic, environmental or unknown

• can be hereditary or non hereditary

define hereditary diseases

• passed genetically from parents to offstring

• always due to genetics

• all hereditart diseases are congenital

layers of the skin

• epidermis 

• superficial dermis 

• deep dermis 

• subcutis 

layers of epidermis 

• stratum corneum 

• stratim granulosum 

• stratim spinosum 

• stratim basale

• basement membranes 

where are hereditary skin fragility disorder lesions on the body

• ear folds and ear holes

• lateral pressure points

• lips and oral cavity

• loss of claws or hooves

• dorsal tail

• footpads

• areas of friction and folds

causes of decreased collagen

• steroids

• solar dermatitis

• ehlders-danlos syndrome

ehlers-danlos syndrome 

• hyperextensible, stretchy and soft skin 

• skin tears and bruising from minor trauma 

• delayed wound healing 

• cigarette paper scars which are thin and fragile 

• possible point laxity 

canine ectodermal dysplasia

• hairlessness and dental abnormalities, seen well in chinese crested dog

• autosomal dominant trait

• hair on hed, feet and tail

• abnormal number of teeth

• abnormal or long nails

canine ectodermal dysplasia health considerations

• protection from stong UV radiation

• skin allergies

• regular moisturizing

KRT71 gene mutation 

• prevents proper hair formation, leading to a near-hairless Sphynx cat

• skin care is eesential! 

color dilution

• onset usually in first year of life, younger in black hair follicular dysplasia

• patchy alopecia may progress to extensive or total alopecia

• blue, fawn, black mostly on the trunk

• distored hairs induce chronic foliicular inflammation

• often associated with recurrent bacterial folliculitis especially dorsally

types of non-inflammatory alopecia

• alopecia x

• flank alopecia

• canine pattern alopecia

alopecia x 

• no systemic signs 

• loss at frictional areas- neck, body trunk, tail, upper hind legs, symmetrical 

• poor hair quality 

• hyperpigmentation 50% 

• xerosis, scales

• rarely pyoderma 

• hair regrowth after trauma, sunburn, punch biopsy

• aesthetic problem, solar exposure 

• genetic! seen in a clone of affected pomeranian 

therapy options for alopecia x

• castration

• deslorelin acettate for intact males

• melatonin may take 3-4 months, up to 12 months

• do not use trilostane or mitotaine, tx should not be mre dangerous than disease!

• microneedling

seasonal flank alopecia

• boxer, airedales, english bulldogs ect

• nonpruritic, unilateral or bilaterally symmetrical, well circumscribed patches of alopecia and hyperpigmentation on the flanks

• worse in the winter, 20% of dogs only have 1 episode

• short day low melatonin lesions

treatment of seasonal flank alopecia 

oral melatonin started 1-2 months before the known onset 

dermatomyositis

• collies and shetland sheepdogs, may be related to impaired circulation

• lesions often appear on pinnae, tail tip, claw folds, face

• papules, vesicles → alopecia and crusting → erosions, ulcers scaring

• lesions usually at young age

• muscle involvement is variabl

diagnosis of mertaomyositis

skin biopsy

electromyography and or muscle biopsies

dermatomyositis diagnosis 

• minimal sun exposure

• medication to enhance circulation pentoxyfylline 

• fatty acids and vitamin E 

• anti-inflammatories