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Dr Byrne
"Para-metabolic" skin disease

in clinics, some 
senior students seem to see some diseases that are sort of a bit less 
common but that you do see now and then, and it turned out these students 
hadn't heard of them before, so he's adding them in to our curriculum 
here.

paraneoplastic diseases, parametabolic diseases...cutaneous 
manifestations of some other disease. 

Metabolic Epidermal Necrosis:

Superficial Necrolytic Dermatitis
Hepatic cutaneous syndrome

uncommon in 
dogs, rare in cats
-liver disease (most often)
-glucagonoma (in humans -> 
necrolytic migratory erythema)

middle aged to older dogs; males most 
commonly

skin signs:
digits and periorificial areas
hocks, elbows, 
scrotum
footpad hyperkeratosis and fissuring

generally affects all feet, 
fairly evenly distributed with reference to severity.

ddx:  pemphigus 
foliaceous, zinc-responsive dermatosis, SLE, dermatophytosis

slide: this 
dog has more crusting than the other dog had, maybe some more exudate 
present. 

other clinical findings - somewhat variable. often the dog is 
sick, sometimes the main complaint is limping from foot pain. 


-lethargy, inappetance, increased ALKP, ALT, hypoaminoacidemia (not 
detected by routine blood tests, however), +/- increased plasma glucagon, 
+/- hyperglycemia
u/s: liver has honeycomb appearance due to 
hyper/hypoechoic regions. 

dx:
dermatopathology most effective method

findings: red, white, and blue sign; parakeratosis (pink/red) on top of 
pale white epidermis with vacuolization; on top of bluish hyperplastic 
epidermis
in the abscence of the area of vacuolization, looks like 
zn-responsive. 

u/s, plasma glucagon, celiotomy
most cases are liver 
related; if you don't find liver problem you may find an operable 
glucagonoma

management: 
remove glucagonoma if present
treat secondary 
infections (pyodermas, pododermatitis)
nutritional management (feed hills 
a/d or other high quality diet)
prognosis poor in most cases (most are 
hepatic)

part of the problem with skin is decreased AA levels in serum 
causing "starvation" of skin; increasing dietary protein/ AA may offset 
these changes and improve the skin. 

cases:
exudative, erythematous, 
interdigital lesions with secondary bacterial infections.

older male 
sheltie with severe footpad hyperkeratosis. painful, hard to walk; some 
peeling, fissures. scrotal skin also affected. 

bichon/maltese type dog 
who did well on nutritional therapy - came in with facial crusting and 
lesions and foot lesions - hyperkeratosis, interdigital irritation. 
wouldn't eat except finally ate a/d and did pretty well on that. 


Paraneoplastic alopecia:
pancreatic or bile duct carcinoma, older cats. 

signs occur rapidly:
ventrally distributed alopecia
remaining hair 
epilates easily
exfoliative or glistening skin
foot pads may fissure

ddx 
other causes of alopecia

other signs: cat sick, lethargic, losing wt, 
abdominal distension, anemia/leukocytosis may be present.

dx: r/o other 
causes of alopecia, abdominal u/s tumor hunt, dermatopathology: 
follicular and adnexal atrophy
poor prognosis

paraneoplastic exfoliative 
dermatitis: associated with thymoma or thoracic lymphoma in older cats; 
possibly increased in red/orange and white cats. unknown mechanism; 
possibly T-cell mediated attack on the epidermis
signs: exfoliative 
lesions starting at head, pinnae; progresses to neck, trunk, limbs; may 
have keratin debris in claw folds

ddx: ectoparasites, dermatophytosis, 
allergy; drug eruption, erythema multiforme; pemphigus foliaceous; SLE, 
cutaneous lymphoma

other signs: anorexia, wt loss, dysphagia, coughing, 
dyspnea, variable lab findings. 

dx: r/o other dz; dermatopathology - 
basal degeneration, interface dermatitis, apoptosis - similar to erythema 
multiforme lesions. chest rads - mass. management: remove thymoma if 
possible- at least one case here did do well after removal. do FeLV/FIV 
testing of course. 

calcinosis cutis:
dystrophic vs metastatic
cushings: 
iatrogenic or naturally occuring; binding of calcium to dermal collagen 
matrix
rottweiler may be over-represented. 

most cases are dystrophic, 
not due to hypercalcemia but rather due to some change in dermal matrix 
or sometihng that promotes deposition of calcium on matrix materials such 
as collagen. 

metastatic type is reare, due to hypercalcemia, usually 
from chronic renal disease, mainly involves footpads.

skin findings: 
firm, gritty papules and plaques; salmon to yellow color; head, dorsum, 
axillae, inguinal. raised, hard, firm; not really exudative unless there 
is secondary bacterial infection or something. 

ddx: neoplasia, 
infiltrative conditions

other clinical findings related to underlying 
disease - almost every case has steroid history in the background, some 
glucocorticoid exposure of some kind.
dermatopathology is easy - 
mineralization of dermal collagen.

slide: firm, dense, heavy granular 
plaques of calcinosis cutis on this rottweiler, he's a  mess. he has hx 
steroid use & renal failure. 

management: discontinue glucocorticoids, 
control cushing's - generally will get better. may take a long time - 2 
to 3 mos or up to a year for this to resolve. thelesions are sort of 
uncomfortable too, though, so you can *try* veterinary DMSO gel product 
topically; this works pretty well to dissolve the calcium BUT can cause 
hypercalcemia b/c the calcium is absorbed back into the body. dogs can 
die from that. so remember to use this therapy carefully, with monitoring 
of serum calcium levels. 

nodular panniculitis:

uncommon, 
multifactorial syndrome
solitary
multiple
dachshunds, poodles, pancreatic 
disease
the lesion type here, the nodular type lesions, have a lot of ddx 
for nasty diseases that can look like this. solitary nodular panniculitis 
- inflammatory condition of panniculus - isn't that uncommon, you might 
see a dog come in with nodular mass, you remove it, it comes back as 
inflammation.
but when youhave multiple nodules, it's usually an 
idiopathic or multifactorial process, some breeds are predisposed (above) 
- used to be called "dachshund boils"

also seen in cases of pancreatic 
disease - why panniculitis occurs is not well understood. some theories: 
damaged pancreas releases lipases which damage adipocytes. 

skin 
findings: SQ nodules, which may ulcerate and drain brown/yellow lipidy 
messy stuff, single lesion - ventrum; multiple lesoins - trunk, neck, 
limbs

slide; some oozing, disgusting brownish stuff coming out. if this 
is severe, the overlying skin dies, necroses as it is doing here. these 
SQ lumps are also sometimes painful. 

ddx: infectious nodular diseases 
especially mycobacteria, dermatophyticmycetomas, systemic fungal 
infections
rabies/vaccine panniculitis
neoplasia

dx: excisional biopsy - 
cultures, dermatopathology. punch biopsy isn't good though. if you took a 
punch biopsy of one of these nodules, all the action is below the dermis, 
if you punch through you probably get a report describing epidermis, 
dermis, and a suggestion of deep infiltrate and a request for deeper 
biopsy. wedge biopsy could work. or double punching - punch through, go 
back in same hold, and punch again. 

management: r/o pancreatic disease; 
then after ruling out infectious causes, start corticosteroids - usually 
will respond fairly well; tetracycline and niacinamide are also sometimes 
helpful - can start while waiting for culture results - this combination 
is antiinflammatory

slide: sheltie with nodular panniculitis - cilpped 
area shows a lot of purpuric skin which is preparing to necrose. note 
shininess to skin - some fibrosis has already occured. 

slide: dalmatian 
with small areas of alopecia near the gluteal areas; deeper nodules are 
palpable. 

dachsie months and months later - permanent scarring 
alopecia, permanent depigmentation. quiescent now. no nodules are 
present. but the damage is permanent. 
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