Vasculitis, Cutaneous

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Vasculitis, Cutaneous

Vasculitis, Cutaneous is the Inflammation of blood vessel walls

 

PATHOPHYSIOLOGY

Primarily type III (immune complex), but type I and type II reactions are possible.

 

SYSTEMS AFFECTED

  • Skin/Exocrine
  • Renal/Urologic—some greyhounds

 

SIGNALMENT

Species

Dog and cat (rare)

 

Breed Predilections

Any age breed or sex may be affected.

 

SIGNS

Historical Findings

Anorexia, depression, pyrexia possible

 

Physical Examination Findings

  • Focal alopecia with scarring and scaling (especially vaccine-induced/lesions over location of vaccination).
  • Necrosis and punctate ulcers, palpable purpura, hemorrhagic bullae or urticaria.
  • Acrocyanosis.
  • Extremities (paws, pinnae, lips, tail, and oral mucosa) may be painful.
  • Pitting edema of the extremities, polyarthropathy, and myopathy possible.

 

CAUSES

  • Idiopathic
  • Drug-induced
  • Vaccine-induced
  • Adverse food reaction
  • Tick-borne diseases (e.g., Rickettsia rickettsii)
  • Infectious
  • Underlying metabolic process (e.g., diabetes)
  • Auto-immune
  • Neoplasia

 

DIAGNOSIS

DIFFERENTIAL DIAGNOSIS

  • Deep pyoderma
  • Ear margin seborrhea
  • Chemical and thermal burn
  • Hypersentitivity reaction
  • Dermatomyositis
  • Cryoglobulinemia
  • Toxic epidermal necrolysis
  • Erythema multiforme
  • Eosinophilic dermatitis
  • Systemic lupus erythematosus
  • Bullous pemphigoid
  • Pemphigus vulgaris
  • Sepsis

 

CBC/BIOCHEMISTRY/URINALYSIS

Normal unless due to underlying metabolic process or infection.

 

OTHER LABORATORY TESTS

  • Serologic testing for parasitic and infectious disease in high-risk areas.
  • Immunodiagnostics—ANA titer, Coombs’ test, and cold agglutinin tests.

 

DIAGNOSTIC PROCEDURES

  • Skin scrapings—demodicosis.
  • Biopsy of early lesion—submit to a dermatopathologist; findings depend on the underlying cause but usually include neutrophilic (leukocytoclastic/non-leukocytoclastic), lymphocytic, eosinophilic, or granulomatous mixed cells in and around the vessels; vascular necrosis and fibrin thrombi may be prominent; perivascular hemorrhage and edema may occur.
  • Representative cultures (e.g., blood, urine, skin) if suspicious of infectious issues.
  • Titers for rickettsial infections.
  • Immunoassay for fungal organisms.

 

PATHOLOGIC FINDINGS

  • May vary according with stage and etiology.
  • Intramural inflammation of vessels, endothelial cell swelling, pale collagen, faded hair follicles, hemorrhage, and edema of surrounding tissue.

 

TREATMENT

APPROPRIATE HEALTH CARE

Underlying disease—first priority in clinical management.

No systemic abnormalities—treat as outpatient.

Systemic disease—inpatient care recommended.

 

NURSING CARE

Adequate wound care may be necessary for cases with severe and extensive ulceration.

 

ACTIVITY

No limitation unless infectious agent suspected.

Isolate if contagious or zoonotic agent suspected.

 

CLIENT EDUCATION

Inform client that the prognosis is guarded until a cause is found.

 

SURGICAL CONSIDERATIONS

Individual (focal) lesions may be surgically excised. Otherwise, dependent on underlying etiology.

 

MEDICATIONS

DRUG(S) OF CHOICE

  • The underlying disease process should be identified and appropriately treated; if drugs or drug-like substances are suspected, they should be discontinued.
  • First-line therapy while awaiting histopathology results, if no drug reaction is suspected—antibiotics.
  • Immune-mediated disease with concurrent vasculitis—prednisolone (0.5–4 mg/kg q24h and taper according to response).
  • Pentoxifylline 10–20 mg/kg PO q8h.
  • Cyclosporine may be considered.
  • Tetracycline and niacinamide each 500 mg q8h for dogs > 10 kg or 250 mg PO q8h for dogs < 10 kg or doxycycline 5 mg/kg PO q12h with niacinamide as with tetracycline.

 

PRECAUTIONS

  • Do not use any medications suspected of causing hypersensitivity.
  • Do not administer tetracycline/doxycycline to pregnant or young animals.

 

PATIENT MONITORING

  • Monitor appropriately during treatment of specific etiology.
  • Pentoxifylline—may decrease blood pressure; may cause excitation; monitor blood pressure if concerned.
  • Doxycycline or tetracycline—possible increased liver enzymes, possible esophageal strictures in cats (doxycycline); monitor liver chemistries.
  • Patients receiving prednisolone, azathioprine, chlorambucil, sulfasalazine, or dapsone—monitor appropriately with CBC, chemistry screen, and urinalysis.
  • Sulfasalazine or dapsone—may decrease tear formation; Schirmer tear test every 2 weeks initially and then routinely.
  • Immuno-suppressive therapies should be reduced to the lowest possible therapeutic dose.

 

POSSIBLE COMPLICATIONS

Sepsis and death from primary cause and/or sequelae if severe.

 

EXPECTED COURSE AND PROGNOSIS

If no underlying disease is found, vasculitis may be difficult to treat and the prognosis is guarded.

 

MISCELLANEOUS

PREGNANCY/FERTILITY/BREEDING

Corticosteroids, sulfasalazine, tetracycline/doxycycline, and dapsone—do not use in pregnant animals.

All drugs should be used with caution in pregnant and breeding animals.

 

ABBREVIATION

ANA = antinuclear antibody