Evaluation of adults with cutaneous features of small vessel vasculitis

DIF: direct immunofluorescence; CBC: complete blood count; CMP: comprehensive metabolic panel; CSVV: cutaneous small vessel vasculitis; IgA: immunoglobulin A; CH50: total hemolytic complement; C3: complement component 3; C4: complement component 4; ANA: antinuclear antibody; anti-dsDNA: anti-double-stranded deoxyribonucleic acid; ANCA: antineutrophil cytoplasmic antibody; HIV: human immunodeficiency virus.

* Refer to UpToDate content on the evaluation of adults with cutaneous vasculitis for details on biopsy technique and lesion selection. The timing, location, and type of biopsy can impact the detection of diagnostic findings.

¶ Alternatively, if there are no signs or symptoms of systemic involvement, a biopsy for DIF microscopy may be reserved for cases in which vasculitis persists for ≥4 weeks. DIF microscopy aids in the identification of IgA vasculitis and other immune complex-mediated vasculitides.

Δ Clinicians with expertise in the diagnosis of cutaneous vasculitis may elect to defer a skin biopsy for patients with all of the following features because many such cases resolve spontaneously within a few weeks:

• Classic lesions of acute CSVV that have persisted for <4 weeks
• A known, removable or treatable inciting factor
• No clinical or laboratory evidence of systemic involvement

◊ Refer to UpToDate content on the evaluation of adults with cutaneous vasculitis for details.

§ Clinical findings of persistent vasculitis include new lesion development or persistence of red or purple lesions. Residual, macular or patchy hyperpigmentation is common after resolution of vasculitis lesions.

¥ Testing for underlying cause of vasculitis typically includes:

• Hepatitis B and C serology
• Serum complement (CH50, C3, C4)
• ANA, anti-dsDNA, anti-Ro, anti-La, anti-RNP, and anti-Smith antibodies
• Rheumatoid factor
• Serum cryoglobulins
• ANCA
• HIV antibody
• Additional laboratory tests or imaging studies based upon signs/symptoms/patient age^◊

‡ Refer to UpToDate content on the management of idiopathic small vessel vasculitis in adults for details.

† Urticarial vasculitis may manifest with individual urticaria lesions that persist for >24 hours, often associated with pain or a burning sensation.