THE cutaneous manifestations of
systemic disease with Professor
Stephen White was a great way to
end a memorable year of CPD
webinars by The Webinar Vet.
Professor White presented a
number of cases which fall into this
curious category in both cats and dogs,
and gave useful advice on how to best
manage these challenging cases.
The feline perspective
Feline
paraneoplastic
alopecia was
the first
condition
discussed by
Professor
White and is
mostly seen in
older cats
with a rapid onset of clinical signs.
Cases present with ventral abdominal
alopecia, glistening skin and dry,
fissured peeling footpads.
These cats may suffer with pruritus,
excessive grooming, and tender feet
leading to an unwillingness to use litter
trays. Some of these cases may also
have secondary Malassezia and
Professor White was keen to stress that
if cats present with generalised
Malassezia, more serious underlying
disease such as feline paraneoplastic
syndrome, cutaneous lymphoma or
pemphigus foliaceous should always be
considered.
The underlying condition, an
exocrine pancreatic adenocarcinoma, is
an aggressive tumour which, at the
point of diagnosis, has more often
than not already metastasised to the
liver and lungs. Skin biopsies reveal
severe atrophy and miniaturisation of
the hair follicles from which a
diagnosis can be made.
These cases have a poor prognosis
despite there being a small number of
reports in literature stating that removal
of the pancreatic tumour can provide
temporary symptomatic relief.
Unfortunately, clinical signs tend to
return within 2-3 months due to
metastasis for which there is no known
therapy.
Exfoliative dermatitis with
thymoma is another condition seen in
older cats which present with non-
pruritic erythematous scaling to the
head sometimes affecting the rest of
the body. These cases are very
exfoliative and may also be suffering
from generalised Malassezia which can
often lead to the presence of crusts.
Histopathology on skin biopsies
will reveal erythema multiforme and
although this may be seen in a number of conditions, it is most commonly
seen secondary to a tumour or
medications. A chest x-ray will confirm
the presence of a thoracic mass and
surgical excision of the associated
thymoma should lead to the resolution
of all clinical signs.
Metastatic pulmonary carcinoma is
a condition seen in cats where there
has been metastasis from a form of
lung tumour to the feet, with the front
paws most likely to be affected.
The clinical signs are dramatic with
swelling and ulceration to the digits and
x-rays reveal almost complete
decimation to P3. The lung tumour is
confirmed by performing a chest x-ray.
The canine perspective
Superficial necrolytic dermatitis
otherwise known as “hepatocutaneous
syndrome” is seen in older dogs.
Professor White has a theory that the
greater the number of names we have
for a condition, the less we are likely to
know about it, giving an indication of
how challenging these cases are likely
to be.
We don’t know what the underlying
cause is for this particular condition
but generally it does seem to be
associated with very low serum amino
acid levels. Also, at least 20% of dogs
with this syndrome suffer from diabetes mellitus and 5% of
dogs will have a glucagonoma.
These cases present with
clinical signs mimicking
autoimmune dermatological
disease. Crusts, fissures and
ulcers present at
mucocutaneous junctions and
on footpads, with some dogs
showing only lameness at
initial presentation due to the
footpad lesions. However,
unlike the classical
presentation of autoimmune disease, the nasal
planum usually is not
affected.
Any breed can get
this disease but there are
certain breeds which
have a predilection, such
as the Sheltie and
Border Collie.
Skin biopsies and
ultrasound should be
performed to try and
make a diagnosis.
Histopathology on the
skin will show parakeratosis with a high
level epidermal oedema and an
abdominal ultrasound will reveal a
“Swiss cheese”-like liver. A
glucagonoma may also be seen on
ultrasound.
Unfortunately, these cases have a
poor prognosis and 50% of patients
will be euthanased within two months
of diagnosis. However, treatment isn’t
always hopeless and the use of
intravenous amino acids can be
administered over 2-3 days whilst
hospitalised.
Despite being expensive, this
treatment can make a real difference to
the demeanour of some cases and if
effective should be performed every 3-
6 weeks.
Oral products using protein
supplementation with raw egg yolks (3-
6/day), elemental Zn (2mg/kg/day) or
whey protein (1-2
teaspoons/5kg) can
sometimes help although the
success rate is not as high. If
a dog is lucky enough to fall
into the 5% of cases that have
a glucagonoma, then surgical
excision of this tumour
should resolve clinical signs.
Nodular dermatofibrosis
syndrome is a condition seen
primarily in middle-aged
German Shepherds. They
present with pitted nodules,
most commonly found on distal extremities, and
are consistently
associated with renal
cysts,
cystadenocarcinomas or
malignant
adenocarcinomas.
Diagnosis is made by
performing skin
biopsies and ultrasound
of the kidneys.
The formation of
renal cysts is inevitable
and will eventually present on both kidneys, making the
removal of one kidney futile. Prof.
White advised that if cysts aren’t found
on ultrasound initially, it is always
worth checking again in six months.
These renal cysts are usually slow
growing and dogs tend to compensate
well and can survive for five years and
more assuming these cysts are benign.
The speaker did discuss a number
of other conditions which fall into this
category including sertoli cell tumours,
hyperadrenocorticism and
hypothyroidism.
The diseases highlighted in this
article were conditions I perceived we
are less familiar with and I would
highly recommend logging into this
webinar available through The Webinar
Vet. Like me you may find some light
is shed on those mystery skin cases
that seem impossible to solve.
