DERMATOLOGY
NECROLYTIC MIGRATORY ERYTHEMA (NME) aka
Superficial Necrolytic Dermatitis, Hepatocutaneous
Syndrome, Metabolic Dermatosis, Metabolic Epidermal Necrolysis: NME is a rare, ulcerative, crusting
condition that affects the mucocutaneous junctions
(muzzle, lips, nose, eyelids, anus, genitalia) and pressure points (elbows, feet). Hyperkeratosis and fissuring of the foot pads commonly occurs. All foot pads
are usually involved and the interdigital spaces and
nail folds are also typically inflamed and crusted. The
paws often become very painful resulting in lameness
and reluctance to walk. Secondary infections with
bacteria, fungi or yeasts are common. The disease is
generally seen in middle aged to older dogs and may
wax and wane. Foot pad and skin lesions are common
early manifestations of this condition and precede or
accompany chronic liver disease (e.g. cirrhosis, druginduced hepatitis (phenobarbital) and chronic active
hepatitis) or very rarely glucagon-secreting pancreatic
tumours (glucagonomas). The lesions are thought to
be manifestations of nutritional abnormalities related
to amino acids, essential fatty acids or zinc. Systemic
signs usually occur later and may include weight loss,
lethargy, anorexia, icterus, polyuria and polydipsia.
Concurrent diabetes mellitus is relatively common
(especially later in the course of the disease). Histopathologic findings of skin biopsies are classic and
highly characteristic.
These include a superficial perivascular to lichenoid
dermatitis, parakeratotic hyperkeratosis, and a marked
intra- and intercellular oedema limited to the upper
half of the dermis. These histologic findings appear
as a red, white and blue colouring band within epidermis. Once a diagnosis of NME has been made, hepatic ultrasonography should be performed. Hepatic
ultrasound usually reveals a hyperechoic network surrounding hypoechoic areas of parenchyma, likened
to a Swiss-cheese or honeycomb appearance. This
pattern is considered pathognomonic in the dog for
NME. There is no effective treatment and the prognosis is guarded. Corticosteroids should not be used
as many of these patients are diabetic or prediabetic.
Temporary improvement may be achieved with nutritional support. Amino acid supplementation either
with intravenous amino acid preparations or with oral
supplementation e.g. egg yolks (1 egg yolk per 5 kg
body mass), essential fatty acids and zinc can be given. A low fibre, highly digestible diet is recommended.
Treatment of the underlying liver disease would be the
best option. Drugs such as colchicine and milk thistle
are often used. Where a glucagonoma can be surgically removed, the skin lesions start to resolve a week
after surgery and completely resolve within 45 days.
Necrolytic migratory erythema of the footpads (http://
www.dermatologyforanimals.
com/faq-38/)
ZINC RESPONSIVE DERMATOSIS: Zinc is very important in ensuring epithelial tissue integrity. Any qualitative or quantitative deficiency in zinc, may therefore
cause skin problems. Two types of zinc responsive
dermatosis have been described.
Type 1 is a syndrome that has been described in
young dogs. It is considered to be a genodermatosis involving a defect in intestinal zinc absorption
and possibly zinc metabolism at cellular level. Nordic
breeds are predisposed with 75% of cases reported in
Siberian Huskies. The age of onset is usually between
6 months and 3 years. This condition mainly affects
the face (lips, ear pinnae, bridge of the nose, periorbital area), foot pads and perianal region. Typical skin
lesions include erythema, scaling and crusting of all
affected areas. Systemic signs, such as pyrexia, are
common. Diagnosis is based on history, lesion distribution and histopathology of skin biopsies. Prognosis
is good, but recurrences are common. Treatment typically consists of zinc therapy (zinc methionine), low
dose prednisolone to help intestinal zinc absorption,
antibiotics in cases of secondary bacterial infections
and keratomodulating shampoos for the skin lesions.
Type 2 is a syndrome seen in large breed puppies on
poorly balanced diets (excessive cereal, phytate or
calcium) or in adult dogs with intestinal malabsorption. Dermatological signs are identical to those seen
with type 1 and systemic signs, in particular pyrexia,
are common. Diagnosis is based on history, clinical
signs and histopathology of skin biopsies. The prognosis is excellent in general. Zinc should be given in
conjunction with a balanced diet for 3 to 4 weeks and
can then be stopped. In cases of malabsorption the
supplementation may be lifelong unless the cause of
the malabsorption can be diagnosed and treated successfully.
A: Zn-responsive dermatitis affecting the feet and elbow
(http://dermvettacoma.com/zinc-responsive-dermatosis/)
B: Zn-responsive dermatitis affecting footpads
(http://www.siberianhuskyhealthfoundation.com/images/Untitled-1.jpg)
FOOT PAD FOREIGN BODIES: Foot pad foreign bodies are very common and easily missed. The entry
wound may be very small and the foreign body not
visible to the naked eye. Glass and other sharp hard
objects are usually the cause. Well localised discomfort is usually present and the patient often presents
with lameness. The treatment is general anaesthetic
and surgical excision or removal.
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