Schnitzler syndrome: heterogeneous immunopathological findings involving IgM-skin interactions

Schnitzler Syndrome: Insights into Its Pathogenesis, Clinical Manifestations, and Current Management

Schnitzler syndrome is a rare disorder characterized by a chronic urticarial rash associated with immunoglobulin M (IgM) monoclonal gammopathy. Schnitzler syndrome shares strong clinicopathologic similarities with monogenic IL-1-mediated autoinflammatory disorders and is now considered an acquired adult-onset autoinflammatory disease. The spectacular effect of interleukin-1 inhibitors demonstrates the key role of this cytokine in the pathogenesis of the disease. However, the physiopathology of Schnitzler syndrome remains elusive, and the main question regarding the relationship between autoinflammatory features and monoclonal gammopathy is still unanswered. The purpose of this narrative review is to describe what is currently known about the pathogenesis of this peculiar disease, as well as to address its diagnosis and management.

New insights on multigenic autoinflammatory diseases

Autoinflammatory diseases are disorders of the innate immune system, which can be either monogenic due to a specific genetic mutation or complex multigenic due to the involvement of multiple genes. The aim of this review is to explore and summarize the recent advances in pathogenesis, diagnosis, and management of genetically complex autoinflammatory diseases, such as Schnitzler's syndrome; adult-onset Still's disease; synovitis, acne, pustulosis, hyperostosis, osteitis syndrome/chronic recurrent multifocal osteomyelitis/chronic non-bacterial osteomyelitis; Adamantiades-Behçet's disease; Yao syndrome; and periodic fever with aphthous stomatitis, pharyngitis, and adenitis syndrome. The PubMed database was screened for relevant articles using free text words and specific search strings. The search was limited to English-language articles, reporting the results of studies in humans, published through March 2021. Evidence from literature suggest that these rare multigenic autoinflammatory diseases can present with different clinical features and the diagnosis of these diseases can be challenging due to a combination of nonspecific manifestations that can be seen in a variety of other conditions. Diagnostic delays and disease complications may occur due to low disease awareness and the lack of pathognomonic markers. The pathogeneses of these diseases are complex and in some cases precise pathogenesis is not clearly understood. Conventional treatments are commonly used for the management of these conditions, but biologics have shown promising results. Biologics targeting proinflammatory cytokines including IL-1, IL-6, TNF-α, IL-17A and IL-18 have been shown to ameliorate signs and symptoms of different multigenic autoinflammatory diseases.

Monoclonal gammopathy of clinical significance: what the rheumatologist needs to know

Monoclonal proteins can provide important information on the diagnosis of several non-malignant systemic inflammatory disorders. At low concentration, they most commonly represent monoclonal gammopathy of undetermined significance (MGUS), whereas high concentrations often signify plasma cell myeloma or B-cell lymphoma. However, several rare inflammatory conditions associated with variable concentrations of monoclonal proteins, systemic symptoms, and organ dysfunction also exist. These conditions are termed monoclonal gammopathies of clinical significance (MGCS). Patients with MGCS might present to rheumatologists with undiagnosed systemic inflammatory disorders and the monoclonal protein provides an important, underappreciated clue for diagnosis. In this Review, we provide an approach to distinguishing MGCS from MGUS and lymphoid neoplasms, focusing on four rare MGCS that rheumatologists must recognise: scleromyxedema, Schnitzler's syndrome, idiopathic systemic capillary leak syndrome (also known as Clarkson's disease), and telangiectasias, elevated erythropoietin and erythrocytosis, monoclonal gammopathy, perinephric fluid collections, and intrapulmonary shunting (known as TEMPI) syndrome.

Schnitzler Syndrome: A Recherche Entity

Schnitzler syndrome (SS) is a rare disease of unknown etiology. Literature suggests that only around 300 well-diagnosed cases have only been reported worldwide and rarely from India. This syndrome has a slight male predominance with a mean age of onset of around 50 years. It is considered an autoinflammatory disease with presentation mimicking adult-onset Still's disease and systemic lupus erythematosus, and its presentation most commonly includes recurrent fever, urticarial rash, arthralgia, and bone pains. The probable pathogenesis is considered to be cytokine-mediated, mostly interleukin- 1 (IL-1), and its association with the NRLP3 gene has been mentioned in a few reports. Herein, we report a case of a 40-year-old female who presented to us with fever, jaundice, rash, and pedal edema, and detailed investigations revealed leukocytosis with low complements, normal bone marrow with an 'M band' in the immunoglobulin M (IgM) region. Skin biopsy was suggestive of leukocytoclastic vasculitis and renal biopsy was suggestive of membranoproliferative glomerulonephritis (MPGN). All autoimmune and viral markers were negative, including cryoglobulins, and by excluding all possible differentials, the diagnosis of Schnitzler syndrome was confirmed. SS is a disease of exclusion and several autoimmune, hematological infections need to be excluded, hence, this requires extensive workup. It's the rarest of rare cases, with a variable presentation, specially pyrexia of unknown origin (PUO) with rash, hence this case will open the physician's vision of undiagnosed cases, and further research will help understand its pathogenesis.

Evidence of B Cell Clonality and Investigation Into Properties of the IgM in Patients With Schnitzler Syndrome

The Schnitzler Syndrome (SchS) is an acquired, autoinflammatory condition successfully treated with IL-1 inhibition. The two main defining features of this late-onset condition are neutrophilic urticarial dermatoses (NUD) and the presence of an IgM monoclonal component. While the former aspect has been extensively studied in this disease setting, the enigmatic paraproteinaemia and its potential consequential effects within SchS, has not previously been thoroughly addressed. Previous studies analyzing clonal B cell repertoires have largely focused on autoimmune disorders such as Systemic Lupus Erythematous (SLE) and hematological malignancies such as Chronic Lymphocytic Leukaemia (CLL), where B-cell clonality is central to disease pathology. The present study uses next-generation sequencing to provide detailed insight into aspects of B cell VDJ recombination and properties of the resulting immunoglobulin chains. An overview of IgH regional dynamics in 10 SchS patients, with a particular focus on CDR3 sequences and VDJ gene usage is reported, highlighting the presence of specific B cell expansions. Protein microarray detected a substantial proportion of autoreactive IgM to nuclear target proteins, though a single universal target was not identified. Together, these genetic and functional findings impart new understanding into this rare disorder.

Rheumatic involvement and bone scan features in Schnitzler syndrome: initial and follow-up data from a single-center cohort of 25 patients

Objective

To report on the characteristics and long-term course of rheumatic manifestations in Schnitzler syndrome (SchS).

Methods

A retrospective cohort study of patients with SchS followed between 2000 and 2020. Inclusion criteria included a diagnosis of SchS (Strasbourg criteria). All available bone scans were reviewed and scored according to the intensity and number of pathological sites. The scintigraphic score was compared with the clinical activity score, CRP level, and treatments.

Results

Twenty-five patients were included. Median age at diagnosis was 68 years. Eighty patients (72%) had SchS-related rheumatic pain. Most patients had a long-standing isolated rash before constitutional and/or rheumatic symptoms appeared. The monoclonal component level was usually very low (IgMκ in 22/25). Rheumatic pain predominated around the knees. Bone scans revealed abnormal tracer uptake in 15/18 (85%). The scintigraphic score correlated with clinical activity (r = 0.4, p < 0.02) and CRP level (r = 0.47, p < 0.01). The scintigraphic score was lower in patients receiving corticosteroids or IL1Ra (interleukin 1 receptor antagonist) than in untreated patients (median scores:2, 0, and 13, respectively; p < 0.05). Two patients developed Waldenström macroglobulinemia. Of the 22 surviving patients, median age at follow-up was 76 years. IL1Ra was used in 13 patients, with dramatic efficacy on both symptoms and bone scan features.

Conclusions

Rheumatic manifestations are very prevalent in SchS. However, bone pain can be misleading and contribute to misdiagnosis. Bone scan abnormalities are very prevalent and correlate with disease activity and treatments. IL1-Ra has a dramatic and durable efficacy but may not be required in every patient early on.

A New Case of Schnitzler Syndrome in Bulgaria

We describe the case of a 74-year-old Bulgarian woman with a long history of chronic urticaria with severe burning sensation, arthralgia and fever. Additional symptoms of Schnitzler such as monoclonal immunoglobulin – kappa component, elevated erythrocyte sedimentation rate and enlarged lymph nodes were detected six years after the onset of the symptoms. The first diagnoses hypersensitive vasculitis and dermatitis were established in 2009. Schnitzler syndrome was recognized and the diagnosis was established 2 years later after some examination tests. The time course of the values of IgM, C-reactive protein, erythrocyte sedimentation rate and neutrophils were presented. The mean value of IgM is 13.8 ± 2.19 g/l, the mean value of erythrocyte sedimentation rate is 48.6 ± 14.46 mm/h and the mean value of C-reactive protein – 29.8 ± 7.34 mg/l. The use of nonsteroid anti-inflammatory drugs throughout the period and corticosteroids prescribed parenterally and orally resulted in the relief of arthralgia and fever.

A Rare but Fascinating Disorder: Case Collection of Patients with Schnitzler Syndrome

Background

Schnitzler syndrome is a rare disorder characterized by a chronic urticarial rash and monoclonal gammopathy (IgM in more than 90% of the cases). It is difficult to distinguish from other neutrophilic urticarial dermatoses, and diagnosis is based on the Strasbourg criteria. Interleukin-1 is considered the key mediator, and interleukin-1 inhibitors are considered first line treatment. Here, we present two cases of Schnitzler syndrome, both successfully treated with anakinra.

Objectives

To increase awareness regarding clinical presentation, diagnosis, and treatment of this rare disorder.

Cases

We describe the clinical features and disease course of two patients with Schnitzler syndrome, diagnosed using the Strasbourg criteria. Both were treated with anakinra with remarkable response to therapy.

Conclusion

Schnitzler syndrome is a rare and underdiagnosed disorder. High suspicion should be maintained in patients with chronic urticaria-like dermatoses, intermittent fevers, and arthralgias. A serum protein electrophoresis and immunofixation should be performed in these patients. The diagnosis is important to recognize as Schnitzler syndrome is associated with malignancy. A lymphoproliferative disorder develops in about 20% of patients at an average of 7.6 years after onset of symptoms. Thus, patients warrant long-term follow-up. IL-1 inhibitors are extremely effective in relieving symptoms and are considered first line therapy.

Schnitzler's syndrome: lessons from 281 cases

Schnitzler’s syndrome is an autoinflammatory disorder characterized by the association of a monoclonal IgM (or IgG) gammopathy, a chronic urticarial rash, and signs and symptoms of systemic inflammation, including fever, arthralgias and bone pain. It was first described in 1972. This review summarizes the clinical features, efficacy of therapies, and follow-up data of the 281 cases that have been reported to date. Also, the results of skin histology, bone imaging, laboratory investigations, and studies of the pathogenesis will be discussed, including the pivotal role of interleukin-1 beta in this disorder.

[Skin manifestations of monoclonal gammopathies]

Whatever their aetiology, monoclonal gammopathies can be associated to several clinical features. Mechanisms are various and sometimes unknown. Skin is frequently involved and may represent a challenging diagnosis. Indeed, skin manifestations are either the presenting features and isolated, or at the background of a systemic syndrome. Our objective was to review the various skin manifestations that have been associated with monoclonal gammopathies.

Clinical and histopathologic review of Schnitzler syndrome: the Mayo Clinic experience (1972-2011)

BACKGROUND

Schnitzler syndrome is a rare multisystem disorder, defined by urticaria and monoclonal gammopathy, that is associated with malignancy. Considered a neutrophilic urticarial dermatosis, previous reports have included patients with leukocytoclastic vasculitis.

OBJECTIVE

We sought to better define the clinical features, histopathology, and outcomes of Schnitzler syndrome.

METHODS

We retrospectively reviewed clinical records and cutaneous histopathology of all patients with Schnitzler syndrome seen at our institution from January 1, 1972, through July 31, 2011.

RESULTS

Of the 20 patients identified, 80% had IgM κ monoclonal gammopathy; others had IgG λ (10%), IgG κ (5%), or IgM κ+λ (5%). Patients had fevers (85%), arthralgias (70%), leukocytosis (70%), increased erythrocyte sedimentation rate (70%), bone pain (50%), lymphadenopathy (40%), and organomegaly (5%); 45% developed a hematologic malignancy. Histopathologic examination (n = 14) showed predominantly neutrophilic perivascular and interstitial inflammation (57%) or predominantly mononuclear cell perivascular inflammation (29%), with eosinophils in 50% of cases. None showed leukocytoclastic vasculitis.

LIMITATIONS

Our study was limited by its retrospective design.

CONCLUSION

We added 20 patients to approximately 100 reported cases of Schnitzler syndrome. Neutrophilic urticarial dermatosis was the most common histopathologic pattern, but mononuclear cells were predominant in many cases and the infiltrates often contained eosinophils. A high index of suspicion and careful clinicopathologic correlation are needed to avoid diagnostic delays in this syndrome associated with hematologic malignancy.

Schnitzler syndrome with cold-induced urticaria

BACKGROUND

Schnitzler syndrome encompasses monoclonal gammopathy, urticaria, inflammation, recurrent fever, bone pain and arthralgia, with occasional lymphadenopathy and/or hepatosplenomegaly. It is a rare condition with approximately 100 cases reported in the literature. To our knowledge, this is the first reported case of cold-induced physical urticaria with Schnitzler syndrome.

MAIN OBSERVATIONS

A 43-year-old woman presented to an allergy and immunology clinic with a 7 year history of chronic urticaria, angioedema with anaphylaxis, monoclonal gammopathy and bone pain. Her urticaria was triggered by cooler temperatures and an ice cube test for cold induced urticaria was positive. In spite of aggressive therapies this patient remains symptomatic.

CONCLUSIONS

Schnitzler syndrome is under-recognized, particularly variants of the classical description of Schnitzler syndrome. Other diseases, especially those of hematologic origin, should be ruled out. This condition is largely refractory to conventional therapies, although novel treatments, such as interleukin-1 receptor inhibitor, may show promise.

Schnitzler's syndrome associated with pancreatitis: a disease of IL-1 dysregulation

Schnitzler's syndrome (SS) is a rare inflammatory disease of unknown origin characterized by chronic urticaria and monoclonal gammopathy (usually IgM) associated with at least two of the following components: fever, arthralgia or arthritis, bone pain, hepato- and/or splenomegaly, lymphadenopathy, elevated erythrocyte sedimentation rate, leukocytosis, and/or abnormal findings on bone morphological investigations. To date, about 100 cases have been described with only 4 being reported in the USA. The mean time to diagnosis from the onset of disease is 5.4 years, given the varied symptoms with which patients may present. The pathogenesis of SS remains unknown but likely involves dysregulation of the IL-1 pathway. We describe here a 48-year-old woman with a monoclonal IgM gammopathy and a 3-year history of chronic pruritic urticarial dermatosis, unexplained fevers, chronic polyarthritis, lymphadenopathy, leukocytosis, hepatomegaly, and weight loss. She also had a history of chronic pancreatitis as well as a family history of recurrent pancreatitis. The diagnosis of Schnitzler's syndrome was made, and she was successfully treated with the IL-1 receptor antagonist, anakinra.

The Schnitzler syndrome

The Schnitzler syndrome is a rare and underdiagnosed entity which is considered today as being a paradigm of an acquired/late onset auto-inflammatory disease. It associates a chronic urticarial skin rash, corresponding from the clinico-pathological viewpoint to a neutrophilic urticarial dermatosis, a monoclonal IgM component and at least 2 of the following signs: fever, joint and/or bone pain, enlarged lymph nodes, spleen and/or liver, increased ESR, increased neutrophil count, abnormal bone imaging findings. It is a chronic disease with only one known case of spontaneous remission. Except of the severe alteration of quality of life related mainly to the rash, fever and pain, complications include severe inflammatory anemia and AA amyloidosis. About 20% of patients will develop a lymphoproliferative disorder, mainly Waldenström disease and lymphoma, a percentage close to other patients with IgM MGUS. It was exceedingly difficult to treat patients with this syndrome until the IL-1 receptor antagonist anakinra became available. Anakinra allows a complete control of all signs within hours after the first injection, but patients need continuous treatment with daily injections.

In many aspects, the Schnitzler syndrome resembles the genetically determined auto-inflammatory syndromes involving activating mutations of the NLRP3 inflammasome. This latter point and its consequences will be addressed.

[Adult-onset Still's disease, Schnitzler syndrome, and autoinflammatory syndromes in adulthood]

Adult-onset Still's disease (AoSD), Schnitzler syndrome, and cases of adult-onset autoinflammatory syndromes [10-15% of cases of familial Mediterranean fever (FMF) and tumor necrosis factor (TNF) receptor-associated periodic syndrome (TRAPS)] are characterized by a genetic predisposition, with increased interleukin (IL)-1beta and IL-18 production and TNF-alpha signaling, respectively. As a result, periodic fever and inflammation at barrier tissues (synovial tissues, serous membranes, and the skin) are encountered in such patients. Pathophysiological insights into these diseases have renewed interest in research on IL-1beta in rheumatic diseases and have opened new therapeutic avenues. Recently published studies have shown that patients with Schnitzler syndrome, methotrexate-refractory AoSD, and colchicine-refractory FMF or contraindications to colchicines in FMF respond well to treatment with the soluble IL-1 receptor antagonist anakinra. For TRAPS patients, the p75 TNF-alpha receptor/Fc-IgG1 fusion protein etanercept is the treatment of first choice.

[Interleukin-1 cytokines, inflammasomes, NOD-signalosomes and autoinflammation]

The understanding of the genetic and immunological basis of human periodic fever syndromes, in particular cryopyrin-associated periodic syndromes (CAPS), has led to important new insights into the pathogenesis of monogenic and complex interleukin-1beta-associated autoinflammatory diseases. Currently the focus of attention is on the nucleotide-binding oligomerization domain (NOD)-like receptors (NLR), which take part in the regulation of the synthesis and maturation of cytokines in the IL-1 families, NOD-signalosomes and inflammasomes.

Schnitzler syndrome: response to anakinra in two cases and a review of the literature

BACKGROUND

Schnitzler syndrome is a rare disease characterized by a chronic urticarial eruption and monoclonal gammopathy, as well as clinical and laboratory signs of inflammation. The pathophysiology is still unknown, although various autoantibody-mediated mechanisms have been described. Complete remission of symptoms has been reported recently in patients with Schnitzler syndrome treated with anakinra, an interleukin-1 receptor antagonist.

METHODS

Two patients with Schnitzler syndrome treated with anakinra therapy are presented.

RESULTS

We report two cases of nearly complete remission of symptoms in Schnitzler syndrome after the initiation of anakinra therapy, and the first observation of a relapse under continuous daily anakinra therapy. A review of the published literature on the treatment of Schnitzler syndrome with anakinra is presented.

CONCLUSIONS

Based on published data, monotherapy with anakinra is currently the most promising treatment for Schnitzler syndrome, because it is able to induce complete remission of symptoms.

Urticaria : a review

Urticaria is often classified as acute, chronic, or physical based on duration of symptoms and the presence or absence of inducing stimuli. Urticarial vasculitis, contact urticaria, and special syndromes are also included under the broad heading of urticaria. Recent advances in our understanding of the pathogenesis of chronic urticaria include the finding of autoantibodies to mast cell receptors in nearly half of patients with chronic idiopathic urticaria. These patients may have more severe disease and require more aggressive therapies. Extensive laboratory evaluation for patients with chronic urticaria is typically unrevealing and there are no compelling data that associate urticaria with chronic infections or malignancy. Pharmacologic therapy consists primarily of the appropriate use of first- and second-generation histamine H(1) receptor antihistamines. Additional therapy may include leukotriene receptor antagonists, corticosteroids, and immunomodulatory agents for severe, unremitting disease. Despite our greater understanding of the pathogenesis of urticaria, the condition remains a frustrating entity for many patients, particularly those with chronic urticaria.

Schnitzler's syndrome: increased levels of bone formation and angiogenesis factors are reduced after successful pefloxacin treatment

Schnitzler's syndrome is characterized by chronic urticaria and monoclonal immunoglobulin (Ig) M gammopathy, with other features including intermittent fever, joint and/or bone pain with radiologic evidence of osteosclerosis, lymphadenopathy, enlarged liver and/or spleen, leukocytosis, and elevated erythrocyte sedimentation rate. The etiology of the syndrome remains obscure, although involvement of various cytokines has been proposed. Bone metabolism and angiogenesis markers are deregulated in Waldenström macroglobulinemia and IgM monoclonal gammopathy of unknown significance, but these markers have not been assessed in Schnitzler's syndrome. Herein, we report a patient with Schnitzler's syndrome who was treated with oral pefloxacin. Serum levels of osteoclast regulators, markers of bone remodeling and angiogenesis cytokines, were measured before treatment and serially after the initiation of treatment. High bone turnover and strikingly elevated levels of angiogenic cytokines were observed at diagnosis. Treatment with pefloxacin resulted in a normalization of the bone remodeling process and a significant reduction of angiogenic cytokines, with rapid and sustained improvement of symptoms, suggesting that these factors might be implicated in the pathophysiology of this syndrome. Furthermore, pefloxacin was proven to be an effective treatment for patients with Schnitzler's syndrome.

Manifestations cutanées associées aux paraprotéines: mécanismes des atteintes cutanées

Disease entities characterized by the presence of paraproteins have a variety of cutaneous manifestations. These manifestations may be classified in the following categories as a function of their mechanisms: * extracutaneous deposition of paraproteins, as in amyloidosis * intravascular paraprotein deposition, as in cryoglobulinemia * cutaneous lesions resulting from the biologic activity of paraprotein, as in patients with normolipemic xanthoma with monoclonal immunoglobulin anti-LDL activity * abnormal cytokine secretion, as in AESOP (adenopathy and extensive skin patch overlying a plasmacytoma) or POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, and skin changes) syndromes * unknown mechanisms.

Schnitzler syndrome: beyond the case reports: review and follow-up of 94 patients with an emphasis on prognosis and treatment

OBJECTIVE

Schnitzler syndrome is a rare disorder characterized by a chronic urticarial rash and monoclonal gammopathy, accompanied by intermittent fever, arthralgia or arthritis, bone pain, and lymphadenopathy. Our objectives are to systematically review disease characteristics of Schnitzler syndrome and collect follow-up information to gain insight into treatment efficacy and long-term prognosis.

METHODS

PubMed and MEDLINE databases (1966-2006) were searched, using the key words "Schnitzler syndrome," and the combination of "urticaria" with "monoclonal gammopathy," "immunoglobulin M (IgM)," or "paraproteinemia," as well as secondary references. Data on a total of 94 patients who met the criteria for Schnitzler syndrome were reviewed. Questionnaires sent to all authors retrieved additional follow-up data on 43 patients, resulting in a mean follow-up of 9.5 years after onset of symptoms, and a follow-up of 20 years or more in 10 patients.

RESULTS

Symptoms, signs, and laboratory findings as found in the 94 patients are reviewed in detail. There have been promising developments in therapeutic options, especially antiinterleukin-1 treatment, which induced complete remission in all 8 patients treated so far. To date, no spontaneous complete remissions have been reported. Patients with Schnitzler syndrome showed no increased mortality during the present follow-up. However, they had a 10-year risk of 15% of developing a lymphoproliferative disorder, most notably Waldenström's macroglobulinemia. Three cases of type amyloid A (AA) amyloidosis associated with Schnitzler syndrome were reported.

CONCLUSIONS

Schnitzler syndrome is a disabling disorder which affects multiple systems and which can be considered as an autoinflammatory syndrome. There are new, effective treatment options, but close monitoring remains warranted because of the increased risk of lymphoproliferative disease.

Partial response to cyclosporine in a patient with Schnitzler's syndrome

Schnitzler's syndrome is an unusual clinical association of chronic urticaria, intermittent fever and monoclonal immunoglobulin M (IgM) gammopathy. The pathogenesis of the urticaria is unclear and treatment is problematic. We describe the case of a 61-year-old woman with a long history of chronic urticaria with severe pruritus, spiking fever and malaise. The IgM-kappa monoclonal component was detected in the patient's serum 4 years after symptom onset. After ineffective treatment with antihistamines and systemic corticosteroids, oral cyclosporine resulted in complete remission of the fever and malaise, which has persisted after an 18-month follow-up. Partial but maintained remission of the urticaria was also observed, allowing corticosteroid doses to be decreased.

Schnitzler syndrome associated with systemic marginal zone B-cell lymphoma

Schnitzler syndrome is a rare condition defined by chronic urticaria and monoclonal IgM gammopathy. Malignant evolution to Waldenström disease (WD) has been reported in several cases. We report a 49-year-old man who developed a marginal zone B-cell lymphoma (MZL) 3 years after the beginning of Schnitzler syndrome. This is the first report of MZL in association with Schnitzler syndrome. IgM gammopathy is a clue for the diagnosis of Schnitzler syndrome. This condition needs to be closely monitored; it can precede the onset of an authentic lymphoproliferative disorder including WD and rarely MZL.

Monoclonal gammopathies and malignancies in patients with chronic urticaria

BACKGROUND

Monoclonal gammopathy of undetermined significance (MGUS) has been described in association with chronic urticaria (CU) in patients with Schnitzler syndrome. Chronic urticaria may be a manifestation of hematologic malignancies.

METHODS

This study was conducted to evaluate the frequency and characteristics of MGUS or malignancy in patients with CU. The Mayo Clinic electronic database was reviewed to identify patients with the diagnosis of CU.

RESULTS

Of the 1639 patients presenting with CU between 1994 and 2001, 797 (49%) underwent laboratory evaluation for the presence of a coexisting monoclonal protein. Forty-seven CU patients had MGUS, 142 had a malignancy, and 24 had both. Fifteen percent of CU patients with MGUS had a hematologic malignancy compared with 0.9% of CU patients without MGUS (P < 0.001). Patients presenting with a new diagnosis of CU at an older age (> 56 years) were more likely to have associated underlying MGUS. The occurrence of MGUS in this group was higher than the reported incidence of MGUS in the general population.

CONCLUSIONS

Patients with CU younger than 43 years were unlikely to have associated MGUS or malignancy. A higher percentage of patients with CU and MGUS had an associated diagnosis of hematologic malignancy.

Beneficial response to anakinra and thalidomide in Schnitzler's syndrome

BACKGROUND

Schnitzler's syndrome is an inflammatory disorder characterised by chronic urticarial rash and monoclonal gammopathy, accompanied by periodic fever, arthralgia or arthritis, and bone pain. The cause and treatment are still unknown.

OBJECTIVE

To assess treatment with thalidomide and an interleukin 1 receptor antagonist, anakinra, in Schnitzler's syndrome.

CASE REPORTS

Three patients with Schnitzler's syndrome are described, one with IgM gammopathy, two with IgG type. In one patient, thalidomide induced complete remission, but was stopped because of polyneuropathy. Anakinra 100 mg daily in all three patients led to disappearance of fever and skin lesions within 24 hours. After a follow up of 6-18 months, all patients are free of symptoms.

CONCLUSION

Anakinra proved to be effective in three patients with Schnitzler's syndrome. This treatment is preferable to thalidomide, which induced a complete remission in one of our patients, as it has fewer side effects.

Schnitzler's syndrome with IgG kappa gammopathy

A seventy-year-old man with a variant type of Schnitzler's syndrome is reported. Physical examination showed pruritic urticarial lesions on the extremities, arthralgia of knee joints, and intermittent fever. Laboratory investigations revealed a high level of IgG, an increased enythrocyte sedimentation rate, urinary Bence-Jones protein, and an M-bow in serum protein electrophoresis, which was shown to be a monoclonal IgG kappa type. Histological examination showed perivascular neutrophil and lymphocytic infiltration into the upper dermis and diffuse neutrophilic infiltration in the middle dermis. One of the clinical features of typical Schnitzler's syndrome is IgM macroglobulinemia, and this is a very rare case of this syndrome with IgG gammopathy.

Schnitzler's syndrome with monoclonal IgG kappa gammopathy: good response to cyclosporin

Schnitzler's syndrome (SS) is a rare entity characterized by the association of chronic urticaria and monoclonal IgM gammopathy. Usually, intermittent fever, arthralgia and elevation of erythrocyte sedimentation rate also occur. We report a patient with the same symptoms, but with monoclonal IgG instead of IgM paraproteinaemia. Histological examination of the urticarial lesions showed signs of leucocytoclastic vasculitis. After 20 years of therapeutic failure, cyclosporin has achieved a total clearance of urticarial lesions in our patient. Two previous similar cases with clinical features of SS and monoclonal IgG immunoglobulin have been described. We suggest our case also represents a variant of SS with IgG gammopathy.

The Schnitzler syndrome. Four new cases and review of the literature

The Schnitzler syndrome is characterized by a chronic urticarial eruption with a monoclonal IgM gammopathy. The other signs of the syndrome include intermittent elevated fever, joint and/or bone pain with radiologic evidence of osteosclerosis, palpable lymph nodes, enlarged liver and/or spleen, elevated erythrocyte sedimentation rate, and leukocytosis. The mean delay to diagnosis is more than 5 years, and this syndrome is of concern to internists and many medical specialists. Patients with this syndrome are often initially considered to have lymphoma or adult-onset Still disease, which are the main differential diagnoses. However, hypocomplementic urticarial vasculitis, systemic lupus erythematosus, cryoglobulinemia, acquired C1 inhibitor deficiency, hyper IgD syndrome, chronic infantile neurologic cutaneous and articular (CINCA) syndrome, and Muckle-Wells syndrome should also be excluded, because diagnosis relies on a combination of clinical and biologic signs and there is no specific marker of the disease. The disease pursues a chronic course, and no remissions have yet been reported. Disabling skin rash, fever, and musculoskeletal involvement are the most frequent complications. Severe anemia of chronic disease is another serious complication. The most harmful complication, however, is evolution to an authentic lymphoplasmacytic malignancy, which occurs in at least 15% of patients. This hematologic transformation can occur more than 20 years after the first signs of the disease, thus patients deserve long-term follow-up. Treatment is symptomatic and unsatisfactory. The skin rash is unresponsive to treatment, and nonsteroidal antiinflammatory drugs, antihistamines, dapsone, colchicine, and psoralens and ultraviolet A (PUVA) therapy give inconstant results. Fever, arthralgia, and bone pain often respond to nonsteroidal antiinflammatory drugs. In some patients, these symptoms and/or the presence of severe inflammatory anemia require steroids and/or immunosuppressive treatment, which ameliorate inflammatory symptoms but do not change the course of the skin rash.