Small Animal Dermatology, 3rd edition

CHAPTER 48 VASCULITIS 701

 Serologic tests may aid diagnosis of tick-related (i.e., rickettsial) disease.

 ANA titer positive in patient with SLE; may also be positive in patients with other

systemic illnesses.

 Occult heartworm test positive in patients with dirofilariasis.

 Angiostrongylus vasoruminfestation diagnosed by fecal examination and cytologic

examination of tracheal wash.

 Radiographs: assist diagnosis of dirofilariasis and angiostronglyiasis.

 Skin scrapings: possible demodicosis (with secondary sepsis).

 Representative cultures (e.g., blood, urine, skin) if CBC, chemistry screen, or urinal-

ysis reveals systemic disease.

 Biopsy representative lesions (wedge-type biopsy rather than “punch biopsy”

sample):

Findings depend on the underlying cause

Subtle changes associated with tissue hypoxia (e.g., follicular atrophy, cell-poor

interface dermatitis, pale-staining collagen)

Neutrophilic (leukocytoclastic/nonleukocytoclastic) vasculitis

Lymphocytic, eosinophilic, granulomatous, or mixed cellular inflammation in

and around the vessels

Vascular necrosis and fibrin thrombi may be prominent

Perivascular hemorrhage and edema may occur

Ischemic dermatopathy

Direct immunofluorescence or immunohistochemistry staining – deposition of

immunoglobulin in vessel walls.

THERAPEUTICS

 First priority: diagnose and treat the underlying disease.

 No systemic abnormalities: treat as outpatient.

 Systemic disease: inpatient care may be required.

 Topical therapy: antiseptic solutions to clean lesions and reduce secondary infection

underneath accumulations of exudates.

 Systemic or severe cases: inform owner that the prognosis may be guarded unless a

cause is found; prognosis is based on the etiology.

Drugs of Choice

 Broad-spectrum antibiotics: first line of therapy while awaiting histopathology

results – cephalexin 22 mg/kg PO BID.

 Pentoxifylline 10–20 mg/kg PO BID to TID.

 Vitamin E 400 IU PO BID.

 Prednisolone 1–2 mg/kg PO BID then tapered to EOD or twice weekly either solely

or in combination with cytotoxic immunosuppressive drugs.

 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