The "other" vasculitis syndromes and kidney involvement.

There are a number of vasculitides that are not confined to a specific vessel size, do not have characteristic features, and/or are not secondary to another disease. Most of these vasculitides are rare in childhood. Behçet disease is representative of this group as it involves vessels of any size on both the arterial and venous side. In addition to renal vascular involvement, Behçet disease may involve the kidney through glomerulonephritis, secondary amyloidosis and, rarely, tubulointerstital involvement. Vasculitis secondary to infections, malignancy, and drugs are not common among children. However, vasculitis may be associated with a number of rheumatic diseases in childhood and the auto-inflammatory syndromes (periodic fever syndromes). Auto-inflammatory syndromes are diseases characterized by periodic attacks of clinical and laboratory inflammation. Studies carried out during the past decade have provided valuable information on the mechanism of inflammation and innate immunity in general. This group of vasculitides is associated with secondary amyloidosis of the kidney if not treated. Hypocomplementemic urticarial vasculitis is an interesting vasculitic disease with frequent kidney involvement. Here, we introduce the reader to the wide scope of these diseases; although rare, such diseases represent a challenge to the nephrologist.