Cutaneous vasculitis is a disorder in which the vessel walls become inflamed with consequent hemorrhage and ischemia. It can affect individuals of all ages and can manifest in different ways ranging from a self-limiting disorder involving one organ to a life-threatening condition involving multiple organs.
Cutaneous vasculitis (CV) is a condition in which inflammation of the vessel wall leads to hemorrhage and ischemia . It can be a primary or idiopathic condition (e.g. polyarteritis nodosa (PAN), Wegener's granulomatosis (WG), Churg-Strauss syndrome (CSS), idiopathic cutaneous leukocytoclastic angiitis) or secondary to drugs (e.g. NSAIDs), infections or systemic diseases (e.g. connective tissue disease, rheumatoid arthritis) and malignancy .
Another classification of CV is based on the size of the vessel wall affected - small vessel vasculitis (SVV) and medium vessel vasculitis (MVV) . SVV is associated with urticaria, palpable purpura, target lesions as well as vesiculobullous lesions while lesions in MVV include subcutaneous nodules, livedo reticularis, ulcer, infarct, digital pitted scars and gangrene   although overlapping clinical features of SVV and MVV have also been reported  in the same patient. The cutaneous lesions are usually found on the lower extremity and their appearance on the upper extremity is an indication of severe and/or systemic disease . Constitutional symptoms like fever, malaise, arthralgias are common to CV of the primary as well as secondary types. Although CV can occur in individuals of all ages, it is commonly seen in adults and has a female preponderance. A majority of the children with CV have Henoch-Schönlein purpura (HSP).
Three patterns of CV presentation and progression have been reported :
CV may be associated with extracutaneous (visceral) vascular inflammation in 20% of the patients and this affects mainly the kidneys   . Severe forms of life-threatening CV have been reported in < 7% patients  .
The diagnosis of CV can be challenging due to its variable clinical presentation. The physician has to not only diagnose the vasculitis but should also identify the underlying condition leading to the vasculitis, order the appropriate laboratory workup, treat the patient and follow-up carefully. After eliciting a detailed history and performing a multi-system physical examination, routine laboratory tests like complete blood count, erythrocyte sedimentation rate, C-reactive protein, renal function tests, and urinalysis are ordered. Specific tests like antinuclear antibody, anti-neutrophil cytoplasmic antibodies (ANCA), perinuclear ANCA (pANCA), rheumatoid factor, and complement levels should be obtained in CV patients despite the absence of clinical features of connective tissue disorders or rheumatoid arthritis or systemic lupus erythematosus. Adult patients with HSP have been reported to have immunoglobulin (Ig)A-type antiphospholipid antibodies  and should be tested for it.
If the etiology of CV has been identified then laboratory tests like serum protein electrophoresis (for paraproteinemia), cryoglobulins, hepatitis C antibody and, HIV should be performed. Bone marrow biopsy is indicated in patients with abnormal peripheral blood smears . Although testing for malignancies is not routinely recommended, it should be performed if the clinical presentation in CV is indicative of it . Blood culture and echocardiography may be indicated in patients with endocarditis.
Skin biopsy of the lesion is the mainstay of CV diagnosis as it differentiates between authentic versus pseudo-vasculitis. The timing of the biopsy, multiple biopsies taken from the most reddish, tender and purpuric cutaneous lesions and extending into the subcutaneously help improve identification of the lesion . Almost all biopsies can detect immunoglobulins in the first 48 hours, although complement can still be detected in a majority of cases after 72 hours . Histology demonstrating pan-dermal small-vessel vasculitis as well as subcutaneous muscular-vessel vasculitis is indicative of a connective tissue disorder, ANCA-associated vasculitis, Behçet disease, or malignancy-associated vasculitis. A concomitant biopsy for direct immunofluorescence evaluation is useful to distinguish between IgA-associated vasculitis (Henoch-Schönlein purpura) and IgG-/IgM-associated vasculitis.