A diagnostic challenge-First case of chronic lymphatic leukemia-associated necrotizing sweet syndrome.

Sweet syndrome, also known as acute febrile neutrophilic dermatosis, is a rare disorder typically characterized by the clinical triad including a sudden onset of fever, painful skin lesions, and neutrophilia. The histopathological findings are a dense neutrophilic infiltrate and oedema of the dermis and epidermis without evidence of a vasculitis. Besides treatment of the underlying cause, sweet syndrome is typically treated with high-dose corticosteroids leading to a relapse-free response in 70% of patients. However, if left unrecognized or untreated, the condition may lead to serious complications. Here, we report on the case of a 38-year-old patient in whom, under the assumption of the presence of necrotizing fasciitis, exarticulation of the right arm was performed. In the absence of pathogen detection and insufficient response to anti-infective therapies, the diagnosis of a sweet syndrome was assumed and, later, confirmed by an excellent response to high-dose administration of systematic glucocorticoids. The case emphasizes the need to be aware of this rare syndrome, which can be easily misdiagnosed due to its close resemblance to infection and stresses the need of further research to define distinct diagnostic tools.

Disseminated Yersinia enterocolitica infection associated to Sweet's syndrome.

We report the case of a young woman sough care for disseminated form of Yersinia enterocolitica infection (pseudoappendicitis with mesenteric lymph node, arthralgia, glomerulonephritis and hepatitis) diagnosed on Western Blot method for the detection of Yersinia antibodies. The patient also presented a rare concomitant cutaneous manifestation, as Sweet's syndrome, confirmed histologically. Neutrophilic dermatosis is an exceptional skin features among post-infectious autoimmune disorders when encountering Yersinia enterocolitica infection in clinical practice.

Myelodysplasia cutis and VEXAS syndrome initially diagnosed as histiocytoid Sweet syndrome: A diagnostic pitfall.

Histiocytoid Sweet syndrome (H-SS) is a histopathological variant of Sweet syndrome (SS) defined by cutaneous infiltration of immature myeloid cells morphologically resembling histiocytes. The association of H-SS with underlying malignancy, particularly myelodysplastic syndromes, is well-established. Myelodysplasia cutis (MDS-cutis) has been proposed to describe cases historically diagnosed as H-SS but characterized by shared clonality of the myeloid infiltrate in skin and bone marrow. Therefore, identifying patients who might have MDS-cutis is critical for the management of the associated hematologic malignancy. VEXAS syndrome, an adult-onset autoinflammatory disease, should also be included in the histopathologic differential diagnosis of H-SS, as it shares clinical and pathologic features with MDS-cutis. Through the presentation of two cases, we aim to highlight the defining features and key clinical implications of MDS-cutis and VEXAS syndrome.

Neonatal Sweet syndrome with associated rectovestibular fistula and review of the literature.

An otherwise healthy 4-week-old term female of Japanese heritage presented with a 1-week history of asymptomatic progressive, generalized skin lesions. The lesion morphology, distribution, and dermatopathology result was consistent with Sweet syndrome. The patient was found to have a congenital type H rectovestibular fistula. This case highlights the rare association of rectovestibular fistula in neonatal Sweet syndrome which has only been described in neonates of Japanese heritage.

A case of mevalonate kinase deficiency, neonatal Sweet syndrome, and inflammatory bowel disease.

Mevalonate kinase deficiency is a group of rare metabolic autoinflammatory disorders that present with recurrent fevers, abdominal pain, arthralgias, adenopathy, and a variety of cutaneous manifestations. The skin findings may mimic cellulitis, erythema elevatum diutinum, IgA vasculitis, and Sweet syndrome, and there is often a morbilliform or urticarial rash and aphthous stomatitis. Mevalonate kinase deficiency is one of the identified monogenic variants that can cause very early onset inflammatory bowel disease (IBD). We present a rare case of a patient with mevalonate kinase deficiency, neonatal Sweet syndrome, and infantile-onset IBD, who has been successfully treated with canakinumab therapy.

Unusual Adverse Events in a Patient With BRAF-Mutated Non-Small Cell Lung Cancer Treated With BRAF/MEK Inhibition.

BRAF/MEK inhibition remains standard of care for treatment of BRAF-mutated non-small cell lung cancer (NSCLC). Although common adverse events (AEs) have been reported through clinical trials and ongoing clinical practice, only a handful of reports have detailed unusual adverse events associated with these medications. This report presents a patient with BRAF-mutated NSCLC treated with dabrafenib and trametinib who experienced 2 unusual AEs-Sweet syndrome and MEK-associated retinopathy-that responded to steroid treatment. The patient was able to continue BRAF/MEK inhibition through a coordinated multidisciplinary approach. This case highlights the importance for all clinicians to recognize unusual AEs associated with BRAF/MEK inhibition, particularly in the setting of expanded use for all BRAF V600E-mutated solid tumors.

Drug-induced Sweet's syndrome: A case/non-case study in the French pharmacovigilance database.

AIMS: Sweet's syndrome is an acute febrile neutrophilic dermatosis first described in 1964 by Robert Douglas Sweet. The pathophysiological mechanism is not fully established; however, several cases of Sweet's syndrome have been reported following drug administration. METHODS: To investigate the existence of pharmacovigilance signals between drugs and the occurrence of Sweet's syndrome, we performed a case/non-case study on reports of 'acute febrile neutrophilic dermatosis' registered in the French pharmacovigilance database. Reporting odds ratio (ROR) with its 95% confidence interval were calculated. RESULTS: Amongthe 994 789 reports recorded in the database, 136 were Sweet's syndrome, of which 50.7% were men and the median age was 59 years (range 15-91). A total of 224 drugs were mentioned as suspects: 21.0% were antibacterials, 19.2% were antineoplastics and 12.1% were immunosuppressants. Median time to onset from drug initiation to the development of Sweet's syndrome was 15 days (range 1-1095). The highest RORs were observed with bortezomib (74.04 [40.8-134.2]), azacitidine (72.14 [29.4-176.9]), perfilgrastim (67.05 [21.2-211.6]), azathioprine (55.46 [34.8-88.4]) and bendamustine (35.84 [11.4-112.8]). CONCLUSIONS: Pharmacovigilance signals have been observed between the occurrence of Sweet's syndrome and colony-stimulating factors, immunosuppressants, antineoplastics and antibiotics. Clinicians should be aware of the potential associations with these drugs and should be encouraged to report any case of drug-induced Sweet's syndrome.

Neutrophilic dermatosis of the dorsal hands: A review of 123 cases.

Neutrophilic dermatosis of the dorsal hands (NDDH) is an uncommon localized variant of Sweet syndrome first described in 1995. It is characterized by tender erythematous plaques, pustules, and bullae on the dorsa of the hands. A total of 123 cases of NDDH are included in this review. The mean patient age was 62.1 years, and there was a slight female preponderance. Overall, 78.0% of cases had bilateral involvement, and other sites were affected in almost a third of cases. Underlying disease was found in ∼40% of patients, with the most common associations being hematologic disorders (gammopathies, myelodysplasias, or malignancies), recent infection, solid organ tumors, and inflammatory bowel disease. Systemic or topical corticosteroids or both were employed in the treatment of 88.1% of cases, while dapsone, colchicine, and tetracyclines were the most common steroid-sparing agents used. Improvement was often rapid and complete resolution the norm. Although uncommon, NDDH is frequently misdiagnosed, and thus, its exact prevalence is probably underestimated. Misdiagnosis might have significant implications, including treatment delays or incorrect management. Moreover, recognition of NDDH is important, since a correct diagnosis should trigger a search for underlying diseases and proper treatment with corticosteroids, steroid-sparing agents, or both, which is almost invariably curative.

VEXAS syndrome (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) for the dermatologist.

In 2020, Beck et al1 described a novel adult autoinflammatory syndrome entitled VEXAS (Vacuoles, E1 enzyme, X-linked, Autoinflammatory, Somatic), a newly-discovered disorder that connected previously unrelated inflammatory syndromes and a prototype for a new class of hematoinflammatory diseases.2 Eighty-nine percent of published cases have documented skin involvement, but despite the high incidence and diagnostic accessibility of skin manifestations, there has been little focus on the dermatological features of VEXAS syndrome thus far. A PubMed search of all published case reports of VEXAS syndrome to date was performed, with inclusion of all cases confirmed by genetic sequencing, and this review summarizes the reported dermatological signs. There have already been 141 confirmed published cases since original publication, 126 of which had documented cutaneous signs.1-34 A wide range of skin presentations are reported, including Sweet-like urticated and tender erythematous nodules, cartilaginous involvement with chondritis, cutaneous vasculitis, and periorbital angiodema.1-34 Many patients had been diagnosed with Sweet syndrome, relapsing polychondritis, polyarteritis nodosa, or erythema nodosum.1-34 Hallmarks of skin histopathology are a neutrophilic dermatosis with coexisting or exclusive leukocytoclastic vasculitis.1 The new classification therefore helps link previously disparate inflammatory skin conditions into a unifying pathophysiological pathway.

Azathioprine hypersensitivity syndrome manifesting as subcutaneous Sweet syndrome and acute pancreatitis.

Azathioprine (AZA) is a commonly used immunosuppressive therapy that has been implicated in a number of cutaneous and systemic inflammatory reactions. Initiation of AZA has been associated with a hypersensitivity syndrome manifesting as acute pancreatitis and Sweet syndrome. Subcutaneous Sweet syndrome is a rare variant of Sweet syndrome where the dominant localization of inflammation is within the subcutaneous fat; it is commonly associated with underlying myeloproliferative disease. However, it has not been reported in the literature as a cutaneous manifestation of AZA hypersensitivity syndrome. We present a unique case of acute pancreatitis and biopsy-proven subcutaneous Sweet syndrome following the initiation of AZA with resolution upon discontinuation.

Acute iododerma presenting as cryptococcoid neutrophilic dermatosis: A clinicopathological pitfall and interesting findings gleaned from a review of the literature.

Iododerma is an uncommon dermatosis caused by excessive iodine exposure and is associated with significant morbidity and mortality. Because of its heterogenous clinical presentation and variable histopathological findings, which depend on the time the skin biopsy is performed, the diagnosis of iododerma is often delayed. We report a rare case of acute iododerma in a woman with end-stage diabetic nephropathy with antecedent radioiodine contrast exposure, presenting histopathologically as cryptococcoid neutrophilic dermatosis (CND). We underscore important clinicopathological pitfalls to avoid misdiagnosis with similar overlapping entities such as Sweet syndrome, review all published cases of CND and draw novel insights into its associated entities.

Neoplastic or inflammatory? A case report of Sweet syndrome with CD30+ cells in a patient with B-lymphoblastic leukemia.

CD30+ cells are typically part of lymphoproliferative disorders but can also be seen in inflammatory dermatoses. We present a case of 47-year-old man with a history of B-lymphoblastic leukemia (B-ALL) who presented with fever, leukocytosis, and papulonodular skin lesions, involving the extremities and trunk. A punch biopsy specimen demonstrated papillary dermal edema with a neutrophilic and histiocytic infiltrate extending into the subcutis. The infiltrate also harbored scattered large cells that were positive for CD30 and demonstrated the immunohistochemical profile of monocytes. A diagnosis of histiocytoid Sweet syndrome with CD30+ cells was made. The case is unique, demonstrating a combination of Sweet syndrome variants with subcutis involvement, histiocytoid morphology, and large CD30+ cells. A prior history of B-ALL and immunohistochemical profile of monocytes with immature morphology broadened the differential diagnosis and added to the diagnostic challenge.

Sweet Syndrome Associated with Active Inflammatory Bowel Disease: A Case Series of a Rare Extra-intestinal Manifestation.

BACKGROUND: Cutaneous extra-intestinal manifestations (EIM) occur in up to 20% of patients with IBD. Information about Sweet syndrome (SS)'s clinical course as a rare cutaneous EIM in IBD is limited to case reports. We present the largest retrospective cohort on the occurrence and management of SS in IBD. STUDY: Electronic medical records and paper charts since 1980 were retrospectively reviewed at a large quaternary medical center to identify all adult IBD patients with histopathology-proven SS. Patient characteristics and clinical outcomes were evaluated. RESULTS: 25 IBD patients with SS were identified; 3 patients were assessed to have AZA-induced SS. The majority of SS patients were female. Median age at diagnosis was 47 years (IQR 33-54 years) and SS appeared at a median of 6.4 years after IBD diagnosis. IBD patients with SS had a high rate of complicated IBD phenotypes (75% extensive colitis in UC and 73% stricturing or penetrating disease in CD, with 100% colonic involvement), as well as frequent co-occurring EIMs (60%). SS correlated with global IBD disease activity. Corticosteroids were an effective therapy for SS in IBD. Recurrence rate of SS was 36%. CONCLUSION: Contrary to previous case reports, SS was a cutaneous EIM occurring late after diagnosis of IBD in our cohort, with occurrences paralleling global IBD disease activity. Although AZA-induced and IBD-associated SS were both effectively treated with corticosteroids, distinguishing them is relevant for future IBD treatment strategies.

Sweet Syndrome: A Review of Published Cases.

Sweet syndrome (SS), the prototypical neutrophilic dermatosis, is characterized by abrupt onset of tender plaques and nodules, classically accompanied by fever and leukocytosis. While management mainly relies on systemic corticosteroids, inadequate response can be seen in some patients that necessitates exploring other treatment options. Early diagnosis of malignancy-associated SS (MA-SS) along with detection of concomitant malignancy is crucial for improving patients' outcomes. Data regarding various clinical manifestations, extracutaneous associations, treatment, and outcomes are poorly characterized in the literature. We aimed to review all published case reports and case series to portray clinical features of SS including extracutaneous manifestations. We also describe reported treatment options and their outcomes to draw attention toward unmet therapeutic needs in the management of SS. In addition, for clinical and practical purposes, we attempted to delineate the distinction between MA-SS and nonmalignant subtypes of SS.

Reactive Neutrophilic Dermatoses in Adult-Onset Immunodeficiency due to Interferon-Gamma Autoantibody and Their Associated Factors.

BACKGROUND: Adult-onset immunodeficiency (AOID) due to interferon-gamma autoantibody is a rare, acquired immunodeficiency disease. Reactive neutrophilic dermatoses (RND), predominantly Sweet syndrome (SS), and generalized pustular eruption have been reported repeatedly. OBJECTIVES: The aims of this study were to describe the cutaneous manifestations in AOID patients and determine the incidence of RND and associated factors using a larger population size than have been previously reported. METHODS: A retrospective chart review of all confirmed AOID cases in Chiang Mai University Hospital from January 2006 to June 2020 was conducted. The demographics and characteristics of RND including type, onset, and laboratory information in every episode of cutaneous manifestations were collected. Generalized estimating equations of binary logistic regression were used to determine the indicators of RND. RESULTS: A total of 146 patients with confirmed AOID were identified. Of these, 57 cases (39%) developed at least one episode of RND. Thirteen cases (23%) of the patients experienced RND twice during the follow-up period. All recurrence of RND displayed the same cutaneous phenotype, with the exception of 2 cases who had both SS and generalized pustular eruption. Finally, 49 episodes of SS and 22 episodes of generalized pustular eruption were included in the analysis. All patients with RND had concomitant active opportunistic infections, of which most were non-tuberculous mycobacterium (NTM) infection. NTM infection (prevalence odds ratio [POR] 2.87), lymphadenopathy (POR 3.30) as well as lower serum alkaline phosphatase (ALP) level (POR 0.71 for every 100-unit increment in ALP) were found to be significantly associated with RND occurrence. CONCLUSIONS: 39% of our AOID patients experienced RND once during the course of the disease. Notable factors associated with RND occurrence were concomitant NTM infection, lymphadenopathy, and lower level of ALP.

Infantile Sweet syndrome following MMRV vaccine.

Sweet syndrome (SS), also called acute febrile neutrophilic dermatosis, is rare in the pediatric population, especially in infants and neonates. We present a case of infantile SS that developed 1 day after the MMRV vaccine; we suggest a possible causal relationship between the MMRV vaccine and SS.

A case of VEXAS syndrome associated with EBV-associated hemophagocytic lymphohistiocytosis.

Vacuoles, E1, X-linked, autoimmunity, somatic (VEXAS) syndrome is characterized by a pathogenic mutation in UBA1, which leads to protean complications including autoimmunity and myelodysplasia. A 56-year-old man with steroid-dependent, later steroid-refractory cutaneous polyarteritis nodosa and Sweet syndrome developed recurrent daily fever, macrocytic anemia, thrombocytopenia, acute hypoxic respiratory failure, and anasarca. He was eventually diagnosed with Epstein-Barr virus (EBV) viremia and hemophagocytic lymphohistiocytosis (HLH). He improved clinically with rituximab, ruxolitinib, and increased glucocorticoids before expiring from Pseudomonas sepsis. UBA1 exon 3 mutational analysis in myeloid enriched peripheral blood revealed a c.122T>C (p.Met41Thr) pathogenic variant, consistent with VEXAS syndrome. We describe the first case of EBV-associated HLH in a patient diagnosed with VEXAS syndrome. Early identification of this syndrome will be important in order to offer potential therapies before life-threatening complications arise.

The regulatory effects of PTPN6 on inflammatory process: Reports from mice to men.

Protein tyrosine phosphatase non-receptor type 6 (PTPN6) is a key regulatory protein in cellular signal transduction in the control of inflammation and cell death. Impairment of PTPN6 is known to be associated with human inflammatory diseases including neutrophilic dermatosis; however, comprehensive studies of PTPN6-associated neutrophilic dermatosis have not clearly identified the relationships involved. Reports from in vitro and in vivo studies revealed that inflammatory cytokines have increased in the white blood cells from PTPN6-knocked out mice, and systemic inflammation was also increased in these mice, resulting in skin inflammation in this model. Reports of PTPN6 regulatory functions through five pathophysiological mechanisms are summarized and discussed here including inhibition of myeloid differentiation primary response 88, enhancement of the regulatory function of receptor-interacting protein kinase, inhibition of receptor-interacting serine/threonine-protein kinase 3/mixed lineage kinase domain-like protein-dependent necroptosis, inhibition of caspase-8-dependent apoptosis, and inhibition of p38/mitogen-activated protein kinase. Treatments by blocking the pathways involved in signal transduction and inflammatory cytokine release are also summarized. Understanding this underlying mechanism could improve therapeutic strategies for neutrophilic dermatosis.

Characteristics of Sweet syndrome in patients with or without malignancy.

Sweet syndrome is a neutrophilic dermatosis occasionally associated with malignancies. Due to its rarity, the clinical features of Sweet syndrome are still unclear. Thus, we aimed to analyze clinical features, treatment, and outcomes of these patients according to associated disease. We conducted a retrospective, longitudinal cohort study from January 2000 to August 2020. We reviewed the medical records of 52 patients with Sweet syndrome. The median age of patients was 57.5 years old (range, 17-84), and 48.1% were female. Of the 52 patients analyzed, 27 patients (51.9%) had malignancy-associated Sweet syndrome. Sweet syndrome was diagnosed concurrently with (N = 8), before (N = 5), and after (N = 14) the diagnosis of malignancy. The idiopathic Sweet syndrome was most common in the non-malignancy group (56.0%). Myelodysplastic syndrome was the most common malignancy associated with Sweet syndrome (47.6%). Leukopenia (p = 0.005), anemia (p < 0.001), and thrombocytopenia (p = 0.008) were significantly associated with malignancy. The majority of patients showed rapid improvement of symptoms after steroid administration. The symptoms of some patients with malignancy did not improve with steroid alone; however, their symptoms often improved when steroids were combined with a treatment for the associated malignancy. Relapse and aggravation of Sweet syndrome were common in the malignancy group. Sweet syndrome showed a broad spectrum of clinical features related to various diseases. Sweet syndrome often occurred as a paraneoplastic feature. Therefore, active systemic evaluation is needed in the first diagnosis of Sweet syndrome without clear etiology.

Unusual drug reaction with features of colchicine toxicity in a patient on colchicine and allopurinol.

A 58-year-old woman was admitted for heart failure and concern for cardiogenic shock. The patient had been recently placed on colchicine and allopurinol, 4 months and 3 weeks, respectively, prior to admission. Upon admission, she had a cutaneous eruption that had started abruptly several days after allopurinol initiation. It included multiple erythematous papules with scant scale on the forearms and numerous erythematous papules on the legs. Because of the varied morphologic presentation, biopsies from both the thigh and forearm were performed for a suspected drug reaction. The specimen from the thigh showed a superficial-dermal, band-like lymphocytic infiltrate with dyskeratosis and numerous intraepidermal mitotic figures predominantly in metaphase. In addition, there were neutrophils with leukocytoclasia. The specimen from the forearm showed superficial perivascular lymphocytic inflammation and intraepidermal dyskeratosis with mitotic figures similar to the thigh biopsy specimen but without a dermal neutrophilic infiltrate. An unusual drug eruption with features of colchicine toxicity was favored. Colchicine toxicity is not a commonly encountered clinical scenario and cutaneous findings have only rarely been described. Herein we report an exceedingly rare case of an unusual drug reaction with "colchicine figures" (i.e., ring-shaped mitotic figures arrested in metaphase) consistent with colchicine toxicity.