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168 Cutaneous Manifestations of Systemic Disease 1487

treatment to maintain remission. Zinc methionine is a hairless areas exposed to light. In addition to skin disease,
VetBooks.ir commonly used veterinary preparation. The dose of ele- other manifestations include polyarthritis, hematologic
changes, protein‐losing nephropathy, and other signs.
mental zinc is 2–3 mg/kg per day. The addition of low‐
dose corticosteroids has also been reported to benefit
The diagnosis of SLE can be difficult. Criteria for the
patients not responding adequately to zinc supplementa- German shepherd dogs are predisposed to SLE.
tion. The intravenous administration of zinc sulfate has diagnosis of canine SLE include the presence of a posi-
been described in patients with a poor response. Young tive antinuclear antibody (ANA) titer as well as a number
dogs with syndrome II zinc‐responsive dermatosis show of other clinical and laboratory findings. The reader is
a dramatic response to zinc and dietary correction, but referred to other sections within this book for a more
do not require lifelong supplementation. thorough discussion of these criteria. Skin biopsies can
be helpful but although the classic changes of SLE are
quite suggestive, the histopathologic findings in SLE are
Feline Pansteatitis
variable. Direct immunofluorescence or immunohisto-
This rare condition has been reported in cats eating diets chemistry can be used to demonstrate immunoglobulin
high in polyunsaturated fatty acids (PUFAs) such as red and complement at the dermoepidermal junction.
tuna, without adequate vitamin E consumption. PUFAs The prognosis for dogs with SLE is guarded, but some
increase oxidative stress through free radical production. patients can be controlled effectively for years. The
Affected cats show inflammation and necrosis of subcu- disease is highly variable in its severity, which can
taneous and intraabdominal fat resulting in firm, painful also wax and wane. Corticosteroids are used most often,
nodules. They are often lethargic, anorexic, febrile, and frequently with the addition of steroid‐sparing agents.
painful with movement and palpation.
The diagnosis is made by histopathology coupled with
a suggestive dietary history. Vitamin E supplementation Vascular Diseases
and a dietary change can be used, but the prognosis for A variety of diseases affecting the cutaneous blood ves-
severe cases is poor. sels can result in skin lesions. Vasculitis refers to vascular
diseases in which blood vessels appear to be the target of
an inflammatory response. Although many cases are idi-
Immune‐Mediated Systemic Diseases opathic, vasculitis can be initiated by myriad factors
Causing Cutaneous Manifestations including drugs, rabies vaccination, infectious diseases,
and food allergy. Thus, the term vasculitis describes a
cutaneous reaction pattern rather than an etiologic
Panniculitis
diagnosis.
Panniculitis in dogs and cats can be due to myriad Lesions are often found on the pinnal apex. The foot-
etiologic factors, such as infectious agents, drug pads are also commonly affected with central or marginal
reactions, and immune‐mediated diseases (systemic ulcers. More widespread lesions can also be seen, con-
lupus erythematosus, polyarthritis, or others). Patients sisting of purpura, erythematous plaques, hemorrhagic
with panniculitis should be evaluated for pancreatic bullae, and ulcers. The skin is often the only organ
disease, as panniculitis has been associated with pancre- affected but in some cases, other organs are concurrently
atitis and pancreatic tumors. The reader is referred affected. For example, cutaneous and renal vasculopathy
to Chapter 164 for a more detailed discussion of of greyhounds is associated with renal disease.
panniculitis.
Canine Uveodermatologic Syndrome
Systemic Lupus Erythematosus (SLE)
This rare syndrome consists of granulomatous uveitis
This multisystem autoimmune disease shows highly var- and concurrent depigmenting dermatitis. A genetic basis
iable signs affecting various organs. It is rare in dogs and is present, with akita dogs reported most frequently. The
very rare in cats. Circulating autoantibodies directed uveitis is usually bilateral and acute in onset, with the
against a wide variety of tissue antigens are present. The skin lesions occurring later in most cases. Depigmentation
estimated frequency of skin lesions is 20–50% of affected is seen on the skin of the nasal planum, lips, eyelids, and
dogs and cats. The lesions can consist of mild alopecic occasionally elsewhere. The diagnosis can be made ten-
scarring, scaling, and crusting, to widespread ulcers tatively based on the unique combination of clinical
involving the skin and oral mucosa. Lesions of the nasal signs, and definitely using skin biopsies.
planum more typically seen with discoid lupus erythe- Other systemic diseases with an immune‐mediated
matosus may be present. Some patients exhibit lesions in etiology that cause cutaneous lesions include erythema