Small Animal Dermatology, 3rd edition

CHAPTER 31 LUPUS ERYTHEMATOSUS 471

 Dermatophytosis.

 Metabolic epidermal necrosis.

 Epitheliotropic lymphoma: may start on the planum and rostral aspect of the muzzle

and lips.

 Squamous cell carcinoma: may affect the planum; may occur at a slightly higher inci-

dence in chronic discoid lupus lesions.

 Idiopathic leukoderma leukotrichia (vitiligo): may cause depigmentation of the tissue

and hair without concurrent inflammation.

 Neoplasia-induced vasculitis.

 Infectious diseases must be differentiated from SLE.

DIAGNOSTICS

 CBC/biochemistries: usually normal; thrombocytopenia in 25% of cases of ECLE.

 ANA, LE preparation, and Coombs tests: usually normal or negative except with SLE.

 SLE: nonerosive polyarthritis, proteinuria from glomerulonephritis, hemolytic ane-

mia, leukopenia, thrombocytopenia, polymyositis, high concentration of beta and

gamma globulins on serum electrophoresis.

 Dermatohistopathology from biopsy:
DLE: lymphocytic interface lichenoid dermatitis with pigmentary incontinence,

prominent basal cell apoptosis, variable degrees of dermal mucin and epidermal

atrophy

GDLE: more severe (than DLE) lymphocytic interface dermatitis with basal cell

degeneration; suprabasal and lymphocytic satellitosis of apoptotic basal cells;

pigmentary incontinence, basement membrane thickening

MCLE: lymphocytic interface lichenoid dermatitis with pigmentary inconti-

nence, prominent basal cell apoptosis; basement membrane thickening; erosions

and ulcerations without blistering; changes most prominent at ulcer margins

VCLE: lymphocytic interface dermatitis with dermoepidermal junction vesicu-

lation; basal cell apoptosis

ECLE: lymphocytic interface dermatitis extending into follicular infundibulum

and sebaceous glands; mural folliculitis; basal cell apoptosis

SLE: lymphocytic interface dermatitis with pigmentary incontinence and

basal cell apoptosis; subepidermal vesiculation; leukocytoclastic vasculitis;

panniculitis.

 Direct immunofluorescence or immunohistochemistry staining may reveal

immunoglobulin and complement deposition at the dermoepidermal junction.

THERAPEUTICS

Drugs of Choice

 Cycline antibiotics: tetracycline (250 mg PO TID for dogs<10 kg; 500 mg PO TID

dogs>10 kg); doxycycline (10 mg/kg PO q24h); minocycline (5 mg/kg PO BID); often