Neutrophilic Urticarial Dermatosis.

Neutrophilic urticarial dermatosis (NUD) is a rare form of dermatosis that is poorly understood. It was first described by Kieffer and colleagues as an urticarial eruption that is histopathologically characterized by a perivascular and interstitial neutrophilic infiltrate with intense leukocytoclasia and without vasculitis or dermal edema. NUD clinically presents as a chronic or recurrent eruption that consists of nonpruritic macules, papules, or plaques that are pink to reddish and that resolve within 24 hours without residual pigmentation. NUD is often associated with systemic diseases such as Schnitzler syndrome, lupus erythematosus, adult-onset Still's disease, and cryopyrin-associated periodic syndromes.

Neutrophilic epitheliotropism, proposed as an auto-inflammatory condition of neutrophilic urticarial dermatosis including Schnitzler syndrome, is also observed in Japanese cases.

Schnitzler syndrome (SchS) is a rare autoinflammatory disease characterized by bone pain, recurrent fever, leukocytosis, and elevated C-reactive protein, along with an urticaria-like rash and monoclonal immunoglobulin (Ig)M or IgG gammopathy. Notably, the condition is distinguished by a relatively persistent recurrent urticarial-like rash. Histopathological features observed in the skin comprise diffuse neutrophil infiltration into the dermis, absence of dermal edema, and vascular wall degeneration, all of which classify SchS as a neutrophilic urticarial dermatosis (NUD). Accumulated histological data from skin biopsies of patients with NUD have revealed a sensitive histopathological marker for NUD, acknowledged as neutrophilic epitheliotropism, which has been proposed as reflecting an autoinflammatory condition. In this report, we present three SchS patients: two men (ages 55 and 68) and a woman (age 75), all displaying neutrophilic epitheliotropism in their skin biopsy specimens. Additionally, a review of eight previously reported SchS cases in Japan identified neutrophilic epithliotropism in five cases. These findings suggest that the inclination of neutrophils toward the epithelial tissue could aid in confirming diagnoses of NUD in most cases that need to be differentiated from conventional urticaria. Consequently, we emphasize that acknowledging neutrophilic epithelial predilection as a hallmark of NUD is critical for expediting early diagnosis and appropriate treatment for SchS.

Clinical Presentation of Schnitzler's Syndrome: A Rare Autoimmune Disease.

Schnitzler's Syndrome (SS) is a rare late-onset acquired autoinflammatory disorder which consists of chronic urticaria associated with a monoclonal IgM-kappa gammopathy, arthralgias, skeletal hyperostosis, lymphadenopathy, and recurrent constitutional symptoms. The average age of diagnosis is 51 years with a slight male predominance with a male to female ratio of 1.6. Diagnosis of SS requires the presence of 2 major criteria including chronic urticaria and monoclonal IgM along with at least two of the following minor criteria: recurrent intermittent fevers, bone pain, arthralgias, elevated erythrocyte sedimentation rate (ESR), neutrophilic dermal infiltrate on skin biopsy, and leukocytosis or elevated C-reactive protein (CRP). Early diagnosis and clinical awareness are paramount in SS as it is associated with a 15-20% risk of lymphoproliferative malignancy. The median overall survival is 12.8 years. We present a case of a 39-year-old female with new onset urticaria associated with recurrent fevers and joint pain. Symptoms were refractory to steroids, and high dose antihistamines. Multi-disciplinary evaluation resulted in the ultimate diagnosis of Schnitzler's Syndrome. The patient was ultimately treated with canakinumab (Il-1 inhibitor), with near resolution of symptoms. This case demonstrates the importance of a broad differential diagnosis and maintaining a high clinical suspicion for rare diseases when presented with a complex form of an otherwise common condition.

Schnitzler syndrome refractory to anakinra: successful treatment with canakinumab.

Schnitzler syndrome (SchS) is a rare autoimmune and inflammatory disease mediated by interleukin-1 beta (IL-1ß). Recurrent monoclonal gammopathy and chronic urticarial rash are the symptoms required for diagnosis according to the Strasbourg criteria. The low prevalence of this syndrome (around 300 cases have been reported) and confusion with other inflammatory disorders may delay the diagnosis for up to 5 years. Although the most effective treatment for SchS is anakinra, some patients do not respond to this treatment. We report a case of SchS in a 64-year-old woman with multiple episodes of fever, severe rash, erythema, arthralgia and dyspnea. The patient was successfully treated with canakinumab after anakinra intolerance and failure of colchicine, prednisone, methotrexate and dapsone. After the first dose of canakinumab the skin wounds rapidly improved and the patient did not require any concomitant treatments. The cause of SchS is still unknown and a differential diagnosis is recommended, especially with adult-onset Still´s disease due to their similar symptoms. Canakinumab, a specific anti-IL-1ß antibody, blocks its binding to receptors, thereby preventing IL-1ß-induced gene activation and production of inflammatory mediators. Canakinumab has proven to be an effective drug in SchS, providing an alternative to anakinra.

An unusual presentation of immunoglobulin A gammopathy in a patient with Schnitzler's syndrome.

This case summarizes a 69-year-old woman who presented with a history of recurrent fevers, widespread urticarial rash and generalized myalgias for several years with an eventual diagnosis of Schnitzler's syndrome. This is a rare autoinflammatory condition which typically involves a chronic urticarial rash, monoclonal immunoglobulin M (IgM) or IgG gammopathy. Rapid improvement in above symptoms were noted with anakinra, an interleukin-1 receptor antagonist. We report an unusual case of a 69-year-old woman who presented with an isolated IgA monoclonal gammopathy.

Schnitzler syndrome.

A woman in her late 40s with a history of psoriatic arthritis presented to us with fever, migratory rash, cervical and axillary lymphadenopathy, and generalised myalgia. Her symptoms did not improve with steroids and her inflammatory markers were in the range of 200 mg/dL for C-reactive protein, erythrocyte sedimentation rate of 71 mm/hour and ferritin of 4000 ng/mL. Infectious workup was negative. Haematological malignancy and autoimmune conditions were among the top differentials, and she was eventually diagnosed with Schnitzler syndrome. A multidisciplinary team consisting of internal medicine, rheumatology, infectious disease and haematology-oncology specialists was involved in the care of this patient. We highlight the diagnostic schema that was followed for this rare and unique constellation of symptoms.

Case report: Schnitzler-like syndrome without monoclonal gammopathy.

Schnitzler syndrome is a rare autoinflammatory disorder characterized by urticarial rash, joint pain, recurrent fever, leucocytosis, elevated C-reactive protein (CRP) and serum amyloid A (SAA), and monoclonal IgM or IgG gammopathy. According to the Strasbourg criteria, both urticarial rash and gammopathy are mandatorily required for the diagnosis of Schnitzler's syndrome. However, incomplete variants lacking either skin symptoms or monoclonal gammopathy have also been described. Here, we report a case in which the diagnosis of Schnitzler-like syndrome was made despite the absence of gammopathy, based on neutrophilic dermal inflammation, episodic and excessive increase in inflammatory parameters, and prompt response to anakinra, a soluble IL1 receptor antagonist (sIL-1RA). In addition, we detected neutrophil epitheliotropism, which is highly suggestive of autoinflammatory disease. Using whole-exome sequencing, we were unable to find a causative pathogenic mutation but did find several mutations possibly related to the inflammatory processes in this patient. This and other cases highlight that the existing Strasbourg criteria are too strict to capture Schnitzler-like syndromes that may respond well and rapidly to IL1 inhibition. Recurrent episodes of disease with normalization of inflammatory symptoms in the interval, rapid response to anakinra, and neutrophilic epitheliotropism in a lesional skin biopsy may help confirm the diagnosis of Schnitzler-like syndrome.

Similarities and differences in autoinflammatory diseases with urticarial rash, cryopyrin-associated periodic syndrome and Schnitzler syndrome.

Cryopyrin-associated periodic syndromes (CAPS) and Schnitzler syndrome (SchS) are autoinflammatory diseases that present with urticaria-like rashes. CAPS is characterized by periodic or persistent systemic inflammation caused by the dysfunction of the NLRP3 gene. With the advent of IL-1-targeted therapies, the prognosis of CAPS has improved remarkably. SchS is considered an acquired form of autoinflammatory syndrome. Patients with SchS are adults of relatively older age. The pathogenesis of SchS remains unknown and is not associated with the NLRP3 gene. Previously, the p.L265P mutation in the MYD88 gene, which is frequently detected in Waldenström macroglobulinemia (WM) with IgM gammopathy, was identified in several cases of SchS. However, because persistent fever and fatigue are symptoms of WM that require therapeutic intervention, it is a challenge to determine whether these patients truly had SchS or whether advanced WM was misidentified as SchS. There are no established treatments for SchS. The treatment algorithm proposed with the diagnostic criteria is to use colchicine as first-line treatment, and systemic administration of steroids is not recommended due to concerns about side effects. In difficult-to-treat cases, treatment targeting IL-1 is recommended. If targeted IL-1 treatment does not improve symptoms, the diagnosis should be reconsidered. We hope that the efficacy of IL-1 therapy in clinical practice will serve as a stepping stone to elucidate the pathogenesis of SchS, focusing on its similarities and differences from CAPS.

Summary of the current status of clinically diagnosed cases of Schnitzler syndrome in Japan.

BACKGROUND: Schnitzler syndrome is a rare disorder with chronic urticaria, and there is no report summarizing the current status in Japan. METHODS: A nationwide survey of major dermatology departments in Japan was conducted in 2019. We further performed a systematic search of PubMed and Ichushi-Web, using the keywords "Schnitzler syndrome" and "Japan" then contacted the corresponding authors or physicians for further information. RESULTS: Excluding duplicates, a total of 36 clinically diagnosed cases were identified from 1994 through the spring of 2022, with a male to female ratio of 1:1. The median age of onset was 56.5 years. It took 3.3 years from the first symptom, mostly urticaria, to reach the final diagnosis. The current status of 30 cases was ascertained; two patients developed B-cell lymphoma. SchS treatment was generally effective with high doses of corticosteroids, but symptoms sometimes recurred after tapering. Colchicine was administered in 17 cases and was effective in 8, but showed no effect in the others. Tocilizumab, used in six cases, improved laboratory abnormalities and symptoms, but lost its efficacy after several years. Rituximab, used in five cases, was effective in reducing serum IgM levels or lymphoma mass, but not in inflammatory symptoms. Four cases were treated with IL-1 targeting therapy, either anakinra or canakinumab, and achieved complete remission, except one case with diffuse large B-cell lymphoma. CONCLUSIONS: Since Schnitzler syndrome is a rare disease, the continuous collection and long-term follow-up of clinical information is essential for its appropriate treatment and further understanding of its pathophysiology.

Case report: Successful treatment with tofacitinib and colchicine in a patient with Schnitzler syndrome.

We report a case of late-onset Schnitzler syndrome successfully treated with Janus-activated kinase (JAK) inhibitors and colchicine. Schnitzler syndrome should be considered for recurrent chronic urticaria when accompanied by fever, fatigue, rapid weight loss, and poor response to antihistamine treatment. Skin biopsy, bone marrow biopsy, and electrophoresis help confirm the diagnosis. Early diagnosis and treatment can lead to complete resolution of symptoms. Besides interleukin (IL)-1 and IL-6 inhibitors, JAK inhibitors and colchicine may be considered as other choices of treatment.

Schnitzler Syndrome Presenting as a Fever of Unknown Origin with Elevated Alkaline Phosphatase Levels.

Schnitzler syndrome (SchS) is a rare, acquired, autoinflammatory disease that is sometimes associated with a fever of unknown origin (FUO). Elevated alkaline phosphatase (ALP) stemming from abnormal bone remodeling is a characteristic laboratory finding of SchS and is included in the diagnostic criteria. However, its utility as a clue to the diagnosis of SchS has been under-emphasized. We herein report a case of SchS presenting with a FUO and highly elevated ALP concentration, which led to repeated, unnecessary liver biopsies.

Enfermedad de Still Del Adulto y Síndrome de Schnitzler: ¿formasdistintas del mismo espectro de enfermedad? Un caso de urticariay fiebre recurrente en el anciano / Adult-Onset Still’s Disease and Schnitzler Syndrome: distinct forms of the same disorder spectrum? – a case of recurrent urticaria with fever in the elderly

Adult-onset Still’s disease (AOSD) and Schnitzler syndrome (SchS) are rare, not fully understood, multisystemic and autoinflammatory disorders, with a challenging differential diagnosis. The authors report the case of an elderly man with unexplained fever, arthralgia, weight loss, spleen enlargement, lymphadenopathy,anemia, hyperferritinemia and IgG monoclonal gammopathy. Autoimmunity, infection, haematological disease and malignancy were excluded. The clinicalspectrum fulfilled both AOSD diagnostic criteria and IgG-variant SchS Strasbourg criteria. Symptom resolution was achieved with immunosuppressive therapy,supporting the diagnosis of an autoinflammatory disorder, a diagnostic challenge for the medical team emerging as an unexpected cause of fever in the elderly. (AU)

Case Report: Therapeutic Use of Ibrutinib in a Patient With Schnitzler Syndrome.

Schnitzler syndrome is a rare adult-onset acquired autoinflammatory disorder typically characterized by chronic urticarial rash and immunoglobulin M (IgM) (rarely IgG) monoclonal gammopathy. Its clinical symptoms usually respond well to interleukin-1 blockade therapy, which, however, does not impact the underlying monoclonal gammopathy. Herein, we described a female patient who presented with urticarial rash, recurrent fevers, and fatigue for 7 years. Laboratory investigations revealed IgMκ monoclonal protein and MYD88 L265P mutation, but no lymphoplasmacytic lymphoma on bone marrow examination. She fulfilled the diagnosis of Schnitzler syndrome and was treated with the Bruton tyrosine kinase inhibitor ibrutinib in combination with prednisone. Her symptoms improved dramatically, and the level of IgMκ monoclonal protein also declined. She tolerated the treatment well. This case highlights the potential therapeutic role of Bruton tyrosine kinase inhibitors in Schnitzler syndrome.

A patient with urticarial lesions, recurrent fever, and IgM-type monoclonal gammopathy.

Schnitzler syndrome is a rare acquired autoinflammatory syndrome. It presents with an urticarial rash and a monoclonal gammopathy, usually of the IgM kappa type. In addition, patients can present with bone and/or joint pain, recurrent fever, asthenia, weight loss, myalgia, headache, lymphadenopathy, hepatomegaly, or splenomegaly. An elevation of blood inflammation markers is commonly found. Skin biopsy of the urticarial rash reveals neutrophilic infiltrate, known as neutrophilic urticarial dermatosis. To confirm the diagnosis, two sets of diagnostic criteria have been established. The syndrome shares many features with other autoinflammatory disorders, such as adult-onset Still's disease and NLRP3-auto-inflammatory disorders (NLRP3-AID, formerly known as cryopyrin-associated periodic syndromes, or CAPS). The pathogenesis of the disease is not yet fully understood; however, it is believed that interleukin (IL)-1ß plays a crucial role and explains the excellent effectiveness of IL-1 blocking agents. It is a chronic disease, and some patients develop lymphoproliferative disease, and seldom AA amyloidosis.

A man in his fifties with recurrent urticaria, fever and joint pain. / En mann i 50-årene med tilbakevendende urtikaria, feber og leddsmerter.

BACKGROUND: Schnitzler's syndrome is a rare, acquired and probably underdiagnosed disorder. It is a type of autoinflammatory condition with late onset. CASE PRESENTATION: A man in his fifties had had recurrent urticaria, fever and chronic joint pain during the previous year. After an extensive investigation, no evidence of infection, autoimmune disease or malignancy was found. Blood samples showed moderately elevated SR and CRP, mild thrombocytosis and presence of monoclonal IgM in low concentration (MGUS). The combination of sterile inflammation, joint/muscle pain, urticaria and M-component was consistent with Schnitzler's syndrome. He was placed on a treatment trial with anakinra (interleukin [IL]-1 receptor antagonist) 100 mg x 1 daily, given as a subcutaneous injection. His condition was excellent until one week after the first injection. The initial treatment indicated a good clinical effect of IL-1 blockade, but due to the very unpleasant localised side effects (extensive dermatitis), treatment with anakinra was withdrawn, and canakinumab (monoclonal antibody against IL-1ß) was chosen instead. He responded very well to this treatment and experienced no adverse effects. One year after starting treatment, the patient still has an excellent treatment response. INTERPRETATION: Anakinra is the treatment of first choice for this condition, but this case history illustrates that canakinumab can be tried if anakinra is not tolerated by the patient.

Schnitzler syndrome and Schnitzler-like syndromes.

ABSTRACT: Schnitzler syndrome is a rare disease of adult-onset with main features including chronic urticarial rash, recurrent fever, arthralgia or arthritis, monoclonal gammopathy of undetermined significance (MGUS), and marked systemic inflammation. Schnitzler syndrome is often underdiagnosed. Patients with Schnitzler syndrome may present to dermatologists and allergists for urticaria, hematologists for MGUS, or rheumatologists for arthritis. It is important to recognize Schnitzler syndrome for its remarkable response to interleukin (IL)-1 blockade. Besides, many cases of Schnitzler-like syndromes do not meet the diagnostic criteria of classical Schnitzler syndrome but display excellent response to IL-1 inhibitors. The overly produced IL-1 is the result of a somatic mosaic gain of function mutation of NLRP3 (nucleotide-binding oligomerization domain [NOD]-like receptor [NLR] family pyrin domain containing 3) gene in some patients with Schnitzler-like syndromes. Inflammasome activation is evident in patients with classical Schnitzler syndrome although no NLRP3 gene mutation is identified. Collectively, Schnitzler syndrome and Schnitzler-like syndromes represent a spectrum of IL-1 mediated adult-onset autoinflammatory diseases.

Retention rate of IL-1 inhibitors in Schnitzler's syndrome.

OBJECTIVES: Schnitzler's syndrome is a rare autoinflammatory disease. Clinical response to IL-1 inhibitor drugs has been described, but limited information is available on the long-term efficacy and safety of these agents in Schnitzler's syndrome. METHODS: A retrospective study was conducted of patients with Schnitzler's syndrome fulfilling Strasbourg diagnostic criteria followed in 9 Italian centres. The retention rate of IL-1 inhibitors was evaluated using Kaplan-Meier analysis. RESULTS: Fifteen of 20 patients with Schnitzler's syndrome were treated with IL-1 inhibitors: in total, they received 16 courses of anakinra (median duration 20.0 months [6.0-58.3]), and 8 courses of canakinumab (median duration 19.0 months [13.5-31.0]). The retention rate of IL-1 inhibitors was 73.4% [SE 9.4] at 1 year and 63.6% [SE 10.4] at 2 years. There was no significant difference between the retention rate of anakinra and canakinumab. The retention rate was higher in patients with a definite diagnosis according to the Strasbourg criteria as compared with those with a probable diagnosis (p=0.03). At the last follow-up visit, all patients who started therapy with IL-1 inhibitors were still on treatment, although in some cases with an increased dosage compared to the start of therapy. A sparing effect on the use of conventional synthetic disease-modifying anti-rheumatic drugs and a significant reduction of prednisone dosage (p=0.02) and of serum amyloid A (SAA) levels (p=0.03) were observed. CONCLUSIONS: The retention rate of IL-1 inhibitors in patients with Schnitzler's syndrome was high, particularly in patients with a definite diagnosis according to the Strasbourg criteria, reflecting their effectiveness in the treatment of this syndrome.