1408
A hypersensitivity vasculitis.
A small blood vessel vasculitis.
Associated with fragmentation of neutrophilic nuclei.
A neutrophilic inflammation of small blood vessels and associated with a number of disease processes ref2242ed to as a hypersensitivity vasculitis which predominantly affects the postcapillary venule.
Presenting symptoms include purpurin, malaise, myalgia, and fever.
Oligoarthritis or monoarthritis is present in 40% of cases
More common in whites than in other races.
Equally common in both genders.
Occurs at any age and in childhood is ref2242ed to as Henoch-Schonlein purpura.
50% of cases are idiopathic.
The majority of cases occur after an acute infection or exposure to a new drug.
May be localized to the skin or can be systemic in manifestations.
Involvement of the joints, gastrointestinal organs and kidneys are the most common sites of involvement beyond the skin.
Involvement of the skin alone is associated with a good prognosis.
Purpura is nonblanching and purpuric patches found on the dependent areas of the body with symmetrical distribution of the legs, thighs, and buttocks being typical.
Purpura is nonblanching and indicates extravasation of blood from inflamed postcapillary venules.
Macules are regular and approximately circular.
Skin manifestations may be asymptomatic or associated with itching, burning or pain.
Lesions may be vesicular, bullous, pustular or ulcerated.
Hallmark of this process is a classic palpable purpura.
Lesions regular and approximately circular because red blood cells exude radially in all directions from inflamed and damaged venules.
Arteritis lesions in contrast are irregular due to to vasculitic and throbotic occlusion of arterioles.
Skin may have eruption only or may be associated with collagen vascular diseases, paraproteinemia, exposure to certain foods, medications, infections and rarely malignancy.
Acute or chronic in nature.
Suspected that the process is due to circulating immune complexes, antineutrophil cytoplasmic antibody along with other cell mediators.
Occurs in approximately 10-30 people per million per year.
Prognosis generally good, but if renal, gastrointestinal, lungs, heart or CNS involvement is present it may be associated with mortality.
The course is benign.