Hypersensitivity Vasculitis Workup

Updated: Apr 03, 2020
  • Author: Ruth Ann Vleugels, MD, MPH; Chief Editor: William D James, MD  more...
  • Print

Laboratory Studies

Evaluation of patients with hypersensitivity vasculitis (leukocytoclastic vasculitis) serves 2 purposes: (1) to determine the presence of systemic disease and (2) to identify a potential associated disorder, which can provide prognostic information. Currently, no established routine exists for the workup of hypersensitivity vasculitis; therefore, testing should be prompted by clinical signs and symptoms.

A urinalysis should be performed in all patients to assess for renal disease.

Some authors also include a complete blood cell count, an erythrocyte sedimentation rate or C-reactive protein, and a blood chemistry panel.

Fecal occult blood testing should be considered in all patients with hypersensitivity vasculitis and should be performed in at least those with bowel symptoms.

Serologic studies (eg, antinuclear antibody; antineutrophil cytoplasmic antibody [ANCA], ie, circulating ANCA, perinuclear ANCA, atypical ANCA; rheumatoid factor) should be obtained in patients without an obvious disease cause.

In children and perhaps in some adults, serologic testing for a possible streptococcal infection should be considered (Streptozyme or ASO titer).

Complement levels, including total hemolytic complement (CH100 or CH50), C3 levels, and C4 levels, may be obtained in patients suspected of having lupus erythematosus or urticarial vasculitis.

Serum protein electrophoresis and immunofixation electrophoresis (IFE) to assess for paraproteinemia, cryoglobulins, and hepatitis C antibody should be included for patients without an otherwise-identified cause of hypersensitivity vasculitis. Hepatitis B has been associated with vasculitis in the past; however, it appears that the association may have occurred by virtue of co-infection with hepatitis C (previously termed non-A, non-B). The measurement of hepatitis B surface antigen may not be required in all cases. Cryoglobulins are often not obtained properly; a positive rheumatoid factor should suggest the possibility of cryoglobulins.

HIV testing for patients at high risk for infection and possibly for those with otherwise unidentifiable cause of disease should be considered.

Consider obtaining a skin biopsy for direct immunofluorescence microscopy, which can aid in distinguishing Henoch-Schönlein purpura (HSP) (IgA-associated vasculitis) from other small-vessel vasculitis, which has prognostic significance.


Imaging Studies

Chest radiography is part of the routine evaluation in patients with respiratory symptoms.

Consider assessing the need for visceral angiography for patients with a severe vasculitic syndrome.

Perform cardiac ultrasonography and blood cultures for patients with fever and/or a heart murmur.


Other Tests

Obtain pulmonary function tests for patients with hypocomplementemic urticarial vasculitis syndrome. Also refer these patients to an ophthalmologist to evaluate for uveitis and episcleritis.



Perform a skin biopsy of a relatively fresh (preferably < 24 hours of duration) lesion in most, if not all, adult patients. Biopsies are often not performed in children with suspected vasculitis in whom the clinical presentation is classic. If Henoch-Schönlein purpura (HSP) is suspected, early biopsy with direct immunofluorescence (DIF) is warranted to assess for perivascular deposition of IgA. Consider performing a biopsy of muscle or a biopsy of visceral organs in patients with severe vasculitic syndromes; however, most patients with hypersensitivity vasculitis of the skin do not require such tests.

Obtaining a bone marrow sample may be useful if the peripheral smear is abnormal.


Histologic Findings

A skin biopsy sample reveals the 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; a biopsy sample of a lesion too early or too late in its evolution may not reveal these findings.

The picture of hypersensitivity vasculitis is a pattern that can occur in any vasculitic syndrome but may also occur in nonvasculitic diseases (eg, neutrophilic dermatoses, at the base of a biopsy sample of a leg ulceration, or in some insect bite reactions). Careful clinicopathologic correlation is necessary. Note the image below.

Histopathologic features of leukocytoclastic vascu Histopathologic features of leukocytoclastic vasculitis.