Renal insufficiency with monoclonal gammopathy and urticarial vasculitis

Autoinflammatory diseases and the kidney

The kidney represents an important target of systemic inflammation. Its involvement in monogenic and multifactorial autoinflammatory diseases (AIDs) vary from peculiar and relatively frequent manifestations to some rare but severe features that may end up requiring transplantation. The pathogenetic background is also very heterogeneous ranging from amyloidosis to non-amyloid related damage rooted in inflammasome activation. Kidney involvement in monogenic and polygenic AIDs may present as renal amyloidosis, IgA nephropathy, and more rarely as various forms of glomerulonephritis (GN), namely segmental glomerulosclerosis, collapsing glomerulopathy, fibrillar, or membranoproliferative GN. Vascular disorders such as thrombosis or renal aneurysms and pseudoaneurysms may be encountered in patients with Behcet's disease. Patients with AIDs should be routinely assessed for renal involvement. Screening with urinalysis, serum creatinine, 24-h urinary protein, microhematuria, and imaging studies should be carried out for early diagnosis. Awareness of drug-induced nephrotoxicity, drug-drug interactions as well as addressing the issue of proper renal adjustment of drug doses deserve a special mention and should always be considered when dealing with patients affected by AIDs. Finally, we will explore the role of IL-1 inhibitors in AIDs patients with renal involvement. Targeting IL-1 may indeed have the potential to successfully manage kidney disease and improve long-term prognosis of AIDs patients.

Kidney involvement in the Schnitzler syndrome, a rare disease

The Schnitzler syndrome (SS) is a rare and underdiagnosed entity that associates a chronic urticarial rash, monoclonal IgM (or sometimes IgG) gammopathy and signs and symptoms of systemic inflammation. During the past 45 years, the SS has evolved from an elusive little-known disorder to the paradigm of a late-onset acquired auto-inflammatory syndrome. Though there is no definite proof of its precise pathogenesis, it should be considered as an acquired disease involving abnormal stimulation of the innate immune system, which can be reversed by the interleukin-1 receptor antagonist anakinra. It clearly expands our view of this group of rare genetic diseases and makes the concept of auto-inflammation relevant in polygenic acquired diseases as well. Increasing numbers of dermatologists, rheumatologists, allergologists, haematologists and, more recently, nephrologists, recognize the SS. The aim of this review is to focus on kidney involvement in the SS. Although the literature regarding kidney involvement in the SS is very poor it can be severe, as in our own case here reported, leading us to recommend the systematic search for nephropathy markers in the SS.

Urticarial lesions: if not urticaria, what else? The differential diagnosis of urticaria: part II. Systemic diseases

There are a number of systemic disorders that can manifest with urticarial skin lesions, including urticarial vasculitis, connective tissue diseases, hematologic diseases, and autoinflammatory syndromes. All of these conditions may enter into the differential diagnosis of ordinary urticaria. In contrast to urticaria, urticarial syndromes may manifest with skin lesions other than wheals, such as papules, necrosis, vesicles, and hemorrhages. Lesions may have a bilateral and symmetrical distribution; individual lesions have a long duration, and their resolution frequently leaves marks, such as hyperpigmentation or bruising. Moreover, systemic symptoms, such as fever, asthenia, and arthralgia, may be present. The most important differential diagnosis in this group is urticarial vasculitis, which is a small-vessel vasculitis with predominant cutaneous involvement. Systemic involvement in urticarial vasculitis affects multiple organs (mainly joints, the lungs, and the kidneys) and is more frequent and more severe in patients with hypocomplementemia. Clinicopathologic correlation is essential to establishing a correct diagnosis.

LEARNING OBJECTIVES

After completing the learning activity, participants should be able to distinguish urticarial lesions suggesting diagnoses other than common urticaria; assess patients with urticarial lesions, and suspect systemic diseases presenting with urticarial skin lesions.

Urticarial vasculitis and hypocomplementemic urticarial vasculitis syndrome

Urticarial vasculitis is a clinicopathologic entity in which episodes of urticaria are accompanied by histopathologic features of cutaneous vasculitis. The histopathologic definition of vasculitis varies from report to report. In this article, vasculitis is defined as histopathologic features of blood vessel damage: There should be evidence of leukocytoclasis and vessel wall destruction, which may or may not be accompanied by fibrinoid deposits. Red blood cell extravasation and perivascular inflammatory cell infiltrate also may be present. The extent to which each of these elements must be present has been debated.