Allergic cutaneous vasculitis

Leucocytoclastic vasculitis is a small vessel inflammatory disease mediated mostly by deposition of immune complexes.

• seek dermatological advice
• infections, medications, chemicals, bacteria, viruses, and diseases associated with immune complexes have been accused in the pathogenesis
• may occur as an isolated cutaneous leucocytoclastic vasculitis that presents as palpable purpura most often localized in the lower extremities; if the condition is not isolated then other symptoms may occur such as abdominal pain, arthralgia and renal involvement (1)
• comparatively common condition - accounts for approximately 50% of all cases of cutaneous vasculitis with the remainder having some sort of extracutaneous disease (2)
• the clinical diagnosis of leucocytoclastic vasculitis is confirmed histopathologically by skin biopsy
• in order to determine the cause of the disease, depending on the patient's history, various investigations may be indicated - complete blood cell count, blood cultures, cryoglobulins, serum protein electrophoresis, rheumatoid factor, antinuclear antibody, and autoantibodies to neutrophilic cytoplasmic antigens and complement
  • usually, ANCA and other autoantibodies are not present, and, if detected, the diagnosis of skin-limited disease should then only be made after rigorously excluding the possibility of systemic vasculitis (2)
• once the diagnosis of leucocytoclastic vasculitis is made, emphasis should be on the search for an aetiological factor and the identification of the involved organs
• if possible, the underlying cause should be treated or removed, for example discontinuation of drugs
• prognosis depends on the disease that has the cutaneous leucocytoclastic angiitis as a component, as well as the severity of internal organ involvement. For example, a patient with cutaneous leucocytoclastic angiitis and moderate nephritis as component of Henoch-Schonlein purpura has a much better prognosis than a patient with these same findings as a component of Wegener's granulomatosis

Reference:

• (1) Leucocytoclastic vasculitis: an update for the clinician. Scand J Rheumatol. 2001;30(6):315-22. Review.
• (2) Davies DJ. Small vessel vasculitis. Cardiovascular Pathology 2005; 14 (6): 335-346.