The most important diagnostic criteria for
Schnitzler syndrome include
chronic urticaria, the presence of monoclonal
IgM immunoglobulin, marked
inflammation (
leukocytosis, elevated CRP and erythrocyte sedimentation rate), subfebrile temperatures or
fevers and bone and
joint pains. It is a rare idiopathic disease that may lead to potentially life-threatening complications such as development of secondary
amyloidosis or transformation into malignant lymphoproliferation.
Schnitzler syndrome should be included in differential diagnostics of
chronic urticaria and
fevers of unknown origin. The diagnostic algorithm is based on clinical presentation and serum and urine electrophoreses to detect monoclonal components. Blockade of
interleukin-1 (IL-1), key
cytokine in the pathogenesis of the disease, dominates current therapeutic protocols.
Anakinra (
Kineret), recombinant human
IL-1 receptor antagonist, is the most widely used treatment option. According to literature, disease remission was obtained in all treated patients. Therefore,
anakinra represents a significant diagnostic possibility to differentiate
Schnitzler syndrome from e.g.
monoclonal gammopathy of unknown significance (MGUS) associated with
urticaria of different aetiology.
Biological therapy with
rilonacept (Arcalyst) and
canakinumab (
Ilaris) represents a new treatment alternative for patients, allowing prolonged dosing intervals of 1 and 8 weeks, respectively (compared to 24 hours with
anakinra). The review article also presents findings of various imaging methods (conventional radiography, computed tomography, traditional bone scintigraphy) and photographs of patients with
Schnitzler syndrome before and after
anakinra therapy.
DESIGN: The aim of the review is to draw attention to the existence of this rare autoinflammatory and potentially premalignant condition, present a simple diagnostic algorithm and provide an overview of therapeutic options for the patients.
CONCLUSIONS: