Page 1490 - Clinical Small Animal Internal Medicine

1428 Section 12 Skin and Ear Diseases

may show systemic signs of illness. A localized variant of Lesions are characterized by vesicles that progress to
VetBooks.ir EBA exists that does not have systemic signs. form erosions, ulcers, and crusts. The oral cavity, nasal
planum, periocular region, genitalia, footpads, and con-
Diagnosis is based on the dermatohistopathologic
findings of skin or mucosal biopsy and immunofluores-
cence or immunohistochemistry. Refer to the subepider- cave pinnae can be affected. Hypopigmentation and
atrophic scarring may occur in some cases. The lesions
mal blistering diseases introduction for details about are nonpruritic, but may be painful. Lymphadenopathy
biopsy technique and special testing. Histopathology may be present.
reveals subepidermal bullae. Diagnosis is based on the dermatohistopathologic
Clinical differential diagnoses include bullous pemphi- findings of skin or mucosal biopsy and immunofluores-
goid, mucous membrane pemphigoid, VCLE, pemphigus cence or immunohistochemistry. Refer to the subepider-
vulgaris, severe erythema multiforme, and bullous drug mal blistering diseases introduction for details about
eruptions. biopsy technique and special testing. Histopathology
Treatment involves immunosuppressive therapy such reveals subepidermal bullae.
as glucocorticoids and azathioprine that can be combined Clinical differential diagnoses include bullous pemphi-
with IVIG in refractory cases (see Table 162.1). Disease goid, EBA, VCLE, pemphigus vulgaris, erythema multi-
complications include lethargy, fever, and sepsis. Anemia forme, and bullous drug eruptions. The mucous
and thrombocytopenia were observed in one dog. membranes are markedly affected in MMP. This charac-
Prognosis is guarded to poor because this disease does teristic can be useful in distinguishing MMP from other
not respond readily to treatment. blistering diseases.
Treatment involves immunosuppression. Lesions are
generally not severe, and tend to respond easily to ther-
Linear IgA Disease
apy. Tetracycline and niacinamide should be considered
Linear IgA disease (LAD) is a rare autoimmune disease as initial treatment. Glucocorticoids and other immuno-
of dogs. There are no known breed, age or sex predilec- suppressants may be considered if the lesions are severe
tions. The disease is characterized by ulcerations of the or do not respond readily (see Table 162.1).
mucous membranes, mucocutaneous junctions, and Prognosis is good to guarded. Complications include
skin (particularly of the extremities, axillae, groin, and secondary infections of the lesions.
pawpads). The initial lesions are vesicles, but their tran-
sient nature means they are rarely observed.
Diagnosis is based on the dermatohistopathologic Pemphigus Complex
findings of skin or mucosal biopsy and immunofluores-
cence or immunohistochemistry. Refer to the subepider- History, physical examination, impression smears, and
mal blistering diseases introduction for details about histopathology lead to the diagnosis of diseases
biopsy technique and special testing. Histopathology within the pemphigus complex. The hallmark of dis-
reveals subepidermal bullae with mild to moderate eases in this category is acantholytic keratinocytes
inflammation. Clinical differential diagnoses include (Figure 162.6) and these can be identified on cytology
bullous pemphigoid, mucous membrane pemphigoid, and histology.
EBA, VCLE, systemic lupus erythematosus, pemphigus Trichophyton mentagrophytes and severe pyoderma
vulgaris, severe erythema multiforme, and bullous drug are the primary differentials for pemphigus because
eruptions. acantholytic keratinocytes can occur in these conditions
Treatment has not been reported for this rare disease as well.
in dogs; however, the same immunomodulatory/immu- A direct impression smear from under a moist crust or
nosuppressive drugs mentioned for the other autoim- the content of a pustule will reveal numerous nondegen-
mune blistering diseases can be tried (see Table 162.1). erate neutrophils, acantholytic keratinocytes and some-
Prognosis is guarded due to the paucity of information times eosinophils. Bacteria may be present if secondary
about this disease in dogs. infections occur.
The punch biopsy technique is appropriate for diseases
in this category. The skin should not be shaved or cleaned
Mucous Membrane Pemphigoid
prior to obtaining the biopsy. Crusts should not be
Mucous membrane pemphigoid (MMP) is a rare autoim- removed because they contain acantholytic keratino-
mune blistering disease of dogs and cats that affects the cytes. With rare exceptions, skin devoid of epithelium
mucous membranes and adjacent skin. Dogs are affected should not be biopsied because epithelium is required
in adulthood, with no recognized sex predilection. for a histologic diagnosis. Moist, tightly adhered crusts,
German shepherd dogs may be predisposed. pustules, vesicles or the epithelialized edge of an erosion