Case 78 - Discussion

Uploaded: 2007-11-30, Updated: 2007-12-01

Acute leukocytoclastic vasculitis

• Causes: 1/3 -1/2 idiopathic. Other causes include drugs (antibiotics), infections, foods or food additives, hepatitis C, collagen vascular diseases, and inflammatory bowel disease. Pathogenesis: immune complexes, autoantibodies such as ANCA), inflammatory mediators, and local factors. The exact mechanisms remain unknown.

• Clinical information should be obtained, including history of intravenous drug use, history of hepatitis, history of a transfusion, travel history, symptoms or history of inflammatory bowel disease, and history or symptoms of a collagen vascular disorder, particularly rheumatoid arthritis, lupus erythematosus, or Sjögren syndrome.

• Clinical presentations: Palpable purpura is the most frequent presentation of small-vessel vasculitis. Lesions usually are round and 1-3 mm. They may coalesce to form plaques, and in some instances, they may ulcerate. Palpable purpura is observed most often on the legs, but any surface can be involved. Sometimes, the purpuric lesions are barely palpable.

• Histology: presence of vascular and perivascular infiltration of polymorphonuclear leukocytes with formation of nuclear dust (leukocytoclasis), extravasation of erythrocytes, and fibrinoid necrosis of the vessel walls. This process is dynamic, and a biopsy of a lesion taken too early or too late in its evolution may not reveal these findings. The presence of eosinophils has been correlated with drug associated disease.

• The clinician should be informed immediately about possible systemic manifestations, and the patient may need treatment as soon as possible. Possible symptoms of systemic involvement include fever, arthralgia, arthritis, myalgia, abdominal pain, diarrhea, hematochezia, cough, hemoptysis, sinusitis, paresthesia, weakness, and hematuria.

• http://www.emedicine.com/med/topic2930.htm