Insights Into the Pathogenesis of Sweet's Syndrome

Molecular Characteristics of Sweet Syndrome: A Systematic Review

Sweet syndrome (SS), originally described as acute febrile neutrophilic dermatosis, is a rare inflammatory skin condition, considered the prototype of neutrophilic dermatoses. It is characterised by the sudden onset of well-defined tender papules, plaques and nodules often accompanied by fever, neutrophilia and elevated markers of inflammation. Several variants have been described both clinically and histopathologically. Classifications include idiopathic, malignancy-associated, and drug-induced SS. The exact pathogenesis of SS is still unclear; however, recent findings have shed light on the role of dermal infiltrating neutrophils-in the context of innate immunity, and signalling pathways related to adaptive immunity. To critically analyse the current molecular landscape of SS and discuss the recent evidence supporting novel potential immune mediators and biological signalling pathways involved in SS pathogenesis. The methodology followed PRISMA guidelines and included two bibliographical databases, searching articles published until 17 December 2023. Titles, abstracts and full text were reviewed independently by two assessors, while other two investigators resolved any opinion differences. Of 3303 records identified through database search, 22 articles met the eligibility criteria for inclusion. We considered experimental studies that performed molecular analysis, in terms of cytokines quantification, gene expression and/or immunofluorescence/immunohistochemistry. As for the latter, only studies aimed at characterising the nature of the inflammatory infiltrate and potential mechanisms leading to distinct forms of cutaneous inflammatory cell influx were included. Overall, we described research on 202 SS patients (177 skin biopsies and 25 blood specimens) revealing the predominant role of neutrophil activation and abnormal proliferation as unifying mechanisms in different SS subtypes. Interestingly, we found that hyperactivation of the IL-1 pathway might occur only in a subset of SS patients and adaptive immunity could also play a role in the pathogenic scenario of SS, with a potential significant role of IL-17 axis. This systematic review provides a wealth of evidence on the molecular landscape of SS, although further research is needed to a deeper understanding of the patho-mechanisms of this rare disease and hopefully lead to targeted therapeutic approaches.

Necrotizing Sweet Syndrome of the Hand and Forearm in the Immediate Postoperative Period: Case Report

Necrotizing soft tissue infection (NSTI) is a feared and potentially morbid postoperative complication requiring prompt surgical intervention. Cutaneous conditions that mimic NSTI have been reported and rarely occur in the postoperative period. Sweet syndrome, also known as acute febrile neutrophilic dermatosis, is a dermatologic condition characterized by fever, neutrophil-predominant leukocytosis, and painful skin lesions. Necrotizing Sweet syndrome (NSS) is an aggressive variant that causes a clinical appearance of localized skin necrosis and histologic evidence of necrotic foci extending to the deep aspects of the soft tissues and involving fascia and/or skeletal muscle. Necrotizing Sweet syndrome can be easily mistaken for NSTI. Contrary to infection, Sweet syndrome and NSS are worsened by surgical intervention due to the phenomenon of pathergy and readily respond to corticosteroid treatment. We present the case of a 54-year-old woman who developed NSS following an uncomplicated fasciectomy for Dupuytren disease.

[Canine sterile neutrophilic dermatosis (Sweet-like syndrome): A description of 3 cases]

Three dogs were presented with a sudden onset of erythematous skin lesions, fever, and various extracutaneous signs, assigned to canine sterile neutrophilic dermatosis by clinical, laboratory, and histopathologic examination. This disease is very rare and comparable to Sweet syndrome in humans. According to the 4 forms of SS, the 1st and 3rd cases in this case report could be classified as classic/idiopathic SS. In this context, the respiratory signs may be a prodromal stage of SS preceding the skin lesions or possibly an infection of the respiratory tract was the trigger for SS. The 2nd case, on the other hand, shows a clear and the 3rd case a possible connection to pathergy as a consequence of a previous surgical treatment (case 2 a tibial plateau levelling osteotomy [TPLO] 20 days previously, case 3 a hemilaminectomy 90 days previously). This way, both may be assigned to the 4th form of SS. In all 3 cases, an adverse drug reaction as a trigger cannot be ruled out with certainty, as medication was used before the diagnosis was made in each case. Besides the most common extracutaneous signs such as fever and neutrophilia, immune-hemolytic anemia occurred in 2 of the patients. As therapeutic options, in addition to the established immunosuppressive drugs such as prednisolone, ciclosporin and azathioprine, oclacitinib is also included in the treatment regimen. In addition, administration of an antiplatelet agent (clopidogrel), which may be interpreted as a lesson learnt from the first of the presented cases, that died of pulmonary thromboembolism. In case 2, all drugs were tapered and eventually stopped over a period of 2.5 years and the patient has been without recurrence for 4 years. Case 3 is recurrence-free under therapy.

Sweet Syndrome Presenting with Features of Cellulitis Shortly after Femoral Angioplasty

Neutrophilic dermatosis, or Sweet syndrome, is a cutaneous disorder caused by neutrophilic infiltration in the upper dermis. It has been associated with medications, infections and malignancies but to date it has not been associated with femoral arterial angioplasty or stenting. We present the case of a 75-year-old female who, after angioplasty and stent placement of the right superficial femoral artery, developed right heel pain with ulceration that did not respond to broad antibiotics. She underwent incision and drainage twice without improvement; both times produced negative cultures. She then underwent a punch biopsy by dermatology, which was consistent with acute spongiotic and other neutrophilic dermatoses. She was started on prednisone with immediate improvement of her symptoms. She was discharged to a rehabilitation centre with a prednisone taper and antibiotics. This report highlights the importance of maintaining Sweet syndrome on the differential for cellulitis as it is a rare mimicry of other infectious and non-infectious aetiologies, which are common in the perioperative space. Early treatment is crucial to improve symptoms, outcomes, healthcare cost and potentially the length of stay.

LEARNING POINTS

Sweet syndrome, a rare skin condition related to neutrophil infiltration, may be triggered by angioplasty.Sweet syndrome is easily misdiagnosed as infectious conditions such as cellulitis.

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.

Sweet Syndrome as a Herpetiform Mimic: A Diagnostic Challenge

ABSTRACT

The authors present a singular case of Sweet syndrome (acute febrile neutrophilic dermatosis) manifesting with an unusual herpetiform clinical presentation, underscoring the imperative for its inclusion in differential diagnoses of herpetic infections. A 26-year-old female patient with a systemic lupus erythematosus history presented with facial edema, hyperthermia, cephalalgia, and polyarticular pain. Dermatological examination revealed clustered, vesicle-like papules on erythematous, edematous skin, mimicking herpetic infection. Elevated acute-phase reactants and urine anomalies were noted. Histopathology confirmed Sweet syndrome, characterized by superficial and deep neutrophilic dermatitis, karyorrhexis, and papillary dermal edema. The patient responded to corticosteroid therapy and a brief antibiotic course, resolving both systemic and cutaneous symptoms. This case is remarkable for its atypical herpetiform presentation, a clinical rarity in Sweet syndrome, challenging the conventional diagnostic process. It emphasizes the necessity of considering Sweet syndrome in differential diagnoses when encountering herpetiform lesions, particularly in patients with autoimmune backgrounds. This case contributes significantly to the understanding of Sweet syndrome's clinical variability and highlights the critical role of thorough clinicopathological evaluation in achieving accurate diagnosis in complex dermatological disorders.

Sweet syndrome associated with moderate leukocyte adhesion deficiency type I: a case report and review of the literature

Sweet syndrome is an acute febrile neutrophilic dermatosis characterized by the infiltration of neutrophils into the skin. It may occur idiopathically or be linked to malignancies, inflammatory or autoimmune diseases. Leukocyte adhesion deficiency type I (LAD-I) is an inborn error immunity wherein leukocytes lack adhesion molecules necessary for migration to infection sites due to mutations in the CD18 gene encoding β2 integrins. We present a case of a 16-month-old female initially diagnosed and treated for Sweet syndrome based on histopathological findings with recurrent flare episodes. Subsequent workup revealed LAD-I, making this case the first documented association between Sweet syndrome and LAD-I. Moreover, we reviewed the pertinent literatures detailing the concurrence of neutrophilic dermatosis and immunodeficiency disorders. This case underscores the significance of comprehensive evaluation for Sweet syndrome patients who are refractory to conventional treatments.

Positionally distinct interferon stimulated dermal immune acting fibroblasts promote neutrophil recruitment in Sweet's syndrome

Sweet's syndrome is a poorly understood inflammatory skin disease characterized by neutrophil infiltration to the dermis. Single-nucleus and bulk transcriptomics of archival clinical samples of Sweet's syndrome revealed a prominent interferon signature in Sweet's syndrome skin that was reduced in tissue from other neutrophilic dermatoses. This signature was observed in different subsets of cells, including fibroblasts that expressed interferon-induced genes. Functionally, this response was supported by analysis of cultured primary human dermal fibroblasts that were observed to highly express neutrophil chemokines in response to activation by type I interferon. Furthermore, single-molecule resolution spatial transcriptomics of skin in Sweet's syndrome identified positionally distinct immune acting fibroblasts that included a CXCL1+ subset proximal to neutrophils and a CXCL12+ subset distal to the neutrophilic infiltrate. This study defines the cellular landscape of neutrophilic dermatoses and suggests dermal immune acting fibroblasts play a role in the pathogenesis of Sweet's syndrome through recognition of type I interferons.

Drug-Induced and Malignancy-Associated Neutrophilic Dermatoses in Patients with Hematologic Malignancies: A Single Institution Experience

INTRODUCTION

Neutrophilic dermatoses (NDs) often occur secondary to inflammatory conditions, medication exposure, and hematologic malignancy. While malignancy-associated NDs (MA-NDs) have been well reported among those with hematologic cancers, little is known about drug-induced NDs (DI-NDs) within this population. The objective of this study was to compare the presentations and outcomes of patients with hematologic malignancies who developed MA-NDs and DI-NDs.

METHODS

Cases of ND occurring between 2013 and 2023 among those with hematologic malignancies were identified from the electronic medical records of our institution. Patient characteristics, recent medication exposures, cancer mutations, and disease outcomes were reviewed. Patients were categorized with DI-ND if they were recently exposed to one of four medications known to be commonly associated with ND or were otherwise categorized with MA-ND. We report a descriptive analysis of cases of DI-ND and MA-ND.

RESULTS

We identified 52 patients with ND and co-occurring hematologic malignancy including 16 cases of DI-ND (30.8%) and 36 cases of MA-ND (69.2%). The most common ND in both groups was Sweet's syndrome. Chronic underlying conditions including solid tumors, inflammatory disorders, chronic viral infection, and tobacco use were more common among those with MA-ND. Among those with DI-ND, tyrosine kinase inhibitors were the most commonly associated drugs (43.8%). The most common cancer mutation among those with DI-ND was FLT3 (43.8%), while the most common mutation among those with MA-ND was TP-53 (19.4%). Among those who had died at the time of data collection, 90.0% of those with DI-ND and 66.7% of those with MA-ND died within 1 year of ND diagnosis.

CONCLUSION

Most cases of ND occurring with hematologic malignancies develop secondary to cancer rather than drug exposure. Different cancer mutations may predispose to DI-ND and MA-ND. Further research is needed to establish diagnostic criteria for DI-ND and to determine the pathogenic role of specific cancer mutations, particularly FLT3, in the development of ND.

Sweet syndrome with peripheral neuropathy in a patient with metastatic clear cell renal cell carcinoma

A female patient in her 70s with a newly diagnosed clear cell renal cell carcinoma (ccRCC) with osseous metastasis presented with sudden onset erythematous painful blistering skin lesions on the dorsum of both hands, with associated intermittent fever episodes. Blood tests showed elevated inflammatory marker levels (C reactive protein 257.8 mg/dL, leucocytes 17.79×10⁹/L, with 94% neutrophils). Histologically, there was predominately neutrophil dermal infiltrate without leucocytoclastic vasculitis. The diagnostic criteria of Sweet syndrome were fulfilled. A week later, the patient developed abrupt left-hand palsy, which was confirmed as a medial and ulnar sensorimotor axonal peripheral neuropathy of paraneoplastic origin. The patient was prescribed a course of oral high-dose steroids, which significantly improved the skin lesions. The peripheral nerve palsy improved after 3 months. This case describes the two very rare concurrent paraneoplastic manifestations of ccRCC occurring simultaneously, which have been rarely reported.

Neutrophilic Panniculitides

Neutrophilic panniculitides are a heterogeneous group of inflammatory disorders encompassing many different entities. This review article focuses on the epidemiology, pathogenesis, clinicopathological features, diagnosis, and treatment of selected diseases. Patients often seek care due to systemic involvement, but the variable presentation of panniculitides can present a diagnostic challenge. Most therapeutic modalities for neutrophilic disorders are anecdotal at best with a notable lack of standardization of the responses to medications. There is an urgent need for a larger multi-institutional collaboration to address the unmet needs of these challenging, yet rare conditions.

Pyoderma Gangrenosum: Diagnostic Criteria, Subtypes, Systemic Associations, and Workup

Pyoderma gangrenosum (PG) is an inflammatory neutrophilic dermatosis with variable clinical features. The classic presentation is an ulceration with an erythematous to violaceous undermined border. Extracutaneous manifestations may occur. Associated systemic diseases include inflammatory bowel disease, inflammatory arthritides, and hematologic disorders. The pathophysiologic mechanism of disease is not completely known but likely related to the cumulative impact of inflammation, immune-mediated neutrophilic dysfunction, and genetic predisposition. Incidence is between 3 and 10 people per million but may be greater due to under recognition. In this article, we will discuss the diagnostic criteria, disease subtypes, systemic associations, and workup.

The Neutrophilic Dermatoses, or the Cutaneous Expressions of Neutrophilic Inflammation

Acute febrile neutrophilic dermatosis, or Sweet syndrome, has been described in 1964 and is now considered as a prototypical condition of the group of the neutrophilic dermatoses. Since this time, many clinical conditions have been included in this group and a clinical-pathological classification in 3 subgroups has been proposed. Neutrophilic infiltrates can localize in all internal organs. This defines the neutrophilic disease, which induces difficult diagnostic and therapeutic problems. Autoinflammation is the main pathophysiological mechanism of the neutrophilic dermatoses. There is a special link between myeloid malignancies (leukemia and myelodysplasia) and the neutrophilic dermatoses.

Sweet Syndrome and Neutrophilic Dermatosis of the Dorsal Hands

Sweet syndrome is a rare cutaneous condition with a broad clinical differential diagnosis. It can be classified into 3 subtypes: classic, malignancy-associated, and drug-induced. There are numerous associated disorders and provoking medications. Uncommonly, it can present as a multiorgan disease and cause significant morbidity. Systemic corticosteroids are the gold standard of treatment and yield rapid improvements in both lesions and symptoms. Nonsteroidal therapies may be effective alternatives, although high-quality comparative data are lacking. Some treatments for Sweet syndrome have paradoxically been implicated in the induction of disease.

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.

Comparative immunohistochemical analysis of inflammatory cytokines in distinct subtypes of Sweet syndrome

Background

A dysregulated immune response has been implicated in Sweet syndrome (SS) pathogenesis; however, cytokine profiles across different conditions associated with SS - including adult-onset immunodeficiency (AOID) due to anti-interferon (IFN)-γ autoantibodies - remain unknown.

Objective

To investigate alterations in inflammatory cytokines in skin lesions of distinct subtypes of SS.

Methods

Skin biopsies were collected from 42 AOID- and 52 non-AOID-associated SS patients and 18 healthy controls. The comparative immunohistochemical study was conducted using monoclonal antibodies against interleukin (IL)-1β, IL-6, IL-17, IFN-γ, and tumor necrosis factor-α on paraffin-embedded sections. The quantitative percentage positivity and intensity were calculated using computer-based image analysis.

Results

The results showed stronger and more diffuse dermal immunoreactivity for IFN-γ and IL-17 in the AOID-associated (p < 0.001 and p < 0.001, respectively) and non-AOID-associated SS (p < 0.001 and p < 0.001, respectively) groups. However, no significant differences in the levels of these two cytokines were observed between the AOID- and non-AOID-associated SS groups. Increased expression of IFN-γ together with IL-17 was also noted in almost all subtypes among non-AOID-associated SS.

Conclusions

These results demonstrate that IFN-γ and IL-17 are implicated in immunopathology of all SS subtypes, including AOID-associated SS, despite the presence of anti-IFN-γ autoantibodies.

Case Report: Type 2 Leprosy Reaction Mimicking Sweet Syndrome: A Case Report and Literature Review

Type 2 leprosy reaction is a type of acute inflammation that predominantly affects borderline lepromatous leprosy and lepromatous leprosy patients and occurs before, during, or after therapy. The atypical variant, which resembles Sweet syndrome, could easily lead to misdiagnosis. Here, we report a case of a 52-year-old man who presented with type 2 leprosy reaction that mimicked Sweet syndrome. In addition, we review published cases and summarize their features to raise awareness of this atypical variant to enable improved diagnosis and management.

Rare Autoinflammatory Neutrophilic Dermatoses in Pregnancy: Literature Review

Rare cases of autoinflammatory neutrophilic dermatoses (AINDs) have been reported in patients during pregnancy with associated adverse maternal and fetal outcomes. Due to the rarity and heterogeneous morphology of pregnancy-associated AINDs, clinical diagnosis is often overlooked, and treatment options are limited. In this review, we present the epidemiology, clinical characteristics, therapeutic interventions, maternal and fetal outcomes, and discuss the possible pathophysiology of various pregnancy associated AINDs. Risk factors for the onset and exacerbation of AINDs in pregnancy include older maternal age, disease duration, and specific gestational age. The varied disease courses and conflicting clinical outcomes in both mothers and fetuses demonstrate the importance of symptom recognition and the understanding of the role of pregnancy on AINDs.

Azathioprine hypersensitivity: A Sweet-like syndrome

INTRODUCTION

Azathioprine hypersensitivity can occasionally present as Sweet-like syndrome, a dose-independent side effect characterized by the unanticipated onset of macules, papules, and pustules.

CASE PRESENTATION

A 35-year-old woman with systemic lupus erythematosus presented with complaints of generalized maculopapular rash, facial swelling, and bilateral lower extremity edema with a duration of 4 days and a 2-day history of constitutional symptoms within 2 weeks of the beginning of azathioprine therapy to treat existing lupus nephritis (class 2/3).

DISCUSSION

Patients who experience azathioprine hypersensitivity syndrome can present with erythema nodosum, small-vessel vasculitis, acute generalized exanthematous pustulosis, Sweet syndrome, and nonspecific dermatosis. The following signs and symptoms are used as criteria to diagnose drug-induced Sweet syndrome: (a) abrupt onset of painful erythematous plaques, (b) histopathological evidence of dense neutrophilic infiltrate without evidence of leukocytoclastic vasculitis, (c) temperature higher than 39.7°C, (d) temporal relationship between drug ingestion and clinical presentation, and (e) temporal resolution of lesions after drug withdrawal. Our patient met three out of five criteria and was diagnosed with Sweet-like syndrome.

CONCLUSION

Our case highlights the uncommonly presented azathioprine-induced Sweet-like syndrome that occurs abruptly after the commencement of the offending drug. This diagnosis can be established through basic laboratory workup and skin biopsy findings.

A Case of Bullous Sweet's Syndrome Associated With Esophageal Adenocarcinoma

Sweet's syndrome (SS), or acute febrile neutrophilic dermatosis, characteristically presents with fever, dermal neutrophilic infiltrates, and neutrophilia. It typically manifests as tender erythematous plaques; however, various variants are documented, including bullous. Malignancy-associated Sweet's syndrome (MASS) can present as a paraneoplastic syndrome in those with established cancers or with undiagnosed malignancies. We present a 72-year-old male with a three-day history of a progressive bullous, erythematous papular rash starting on his right forearm and spreading to his extremities, trunk, palms, and soles. It was mildly pruritic but nontender. He had no recent febrile illnesses. On examination, the rash was violaceous with tense bullae overlying edematous targetoid papules coalescing into plaques. Histopathologic analysis of punch biopsies from his abdomen and thigh demonstrated dense inflammatory infiltrates of neutrophils, eosinophils, histiocytes, and lymphocytes, suggestive of neutrophilic dermatosis, or Sweet's syndrome. He was treated with prednisone 1 mg/kg with improvement in his cutaneous symptoms, and a malignancy workup was initiated. Blood work showed elevated free kappa, lambda light chains, lactate dehydrogenase (LDH), and C-reactive protein (CRP) levels. A positron emission tomography (PET) scan revealed lesions in the esophagus and kidney. He was referred to Heme/Onc, GI, and Urology. He was diagnosed with esophageal adenocarcinoma stage IIb and a renal mass. He has since completed neoadjuvant chemotherapy and radiation, is s/p robotic Ivor-Lewis esophagectomy with no evidence of residual carcinoma on pathology, and is undergoing surveillance with imaging every three months for his renal mass. This case highlights the importance of rapid identification of MASS and the impact dermatologists can make in getting these patients the potentially lifesaving care they need.

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.

An uncommon culprit of neutropenic fever: a case of Sweet syndrome following induction therapy for acute myeloid leukemia

Sweet syndrome (SS) is a rare inflammatory disorder characterized by the rapid onset of a characteristically tender rash, fever, and other systemic symptoms. These manifestations are often mistaken for an infection that is not responding to antimicrobials, especially in immunocompromised hosts. We present the case of a 44-year-old woman who developed SS following induction chemotherapy for newly diagnosed acute myeloid leukemia (AML). She exhibited a painful rash on the anterior chest, which spread centrifugally, along with neutropenic fever unresponsive to broad-spectrum antimicrobials. Biopsy of the rash revealed a dense neutrophilic infiltrate within the dermis, confirming the diagnosis of SS. The patient was subsequently treated with systemic steroids with prompt resolution of fevers and improvement of her rash. This case highlights that SS can manifest with a robust neutrophilic infiltrate, even in the context of neutropenia stemming from chemotherapy. SS serves as a crucial consideration in hematologic malignancies, particularly AML, when patients present with fever and cutaneous eruptions. Prompt recognition followed by systemic steroid therapy often leads to symptom resolution.

Athena: Speciality Certificate Examination case for general dermatology and dermatology in primary health care

This Athena case describes a young man with sudden-onset eruption of localized plaques on the right neck in the setting of treatments for recently diagnosed acute myeloid leukaemia.

Characterisation of IL-1 family members in Sweet syndrome highlights the overexpression of IL-1β and IL-1R3 as possible therapeutic targets

Sweet syndrome (SS) as a prototypic neutrophilic dermatosis (NDs) shares certain clinical and histologic features with monogenic auto-inflammatory disorders in which interleukin (IL)-1 cytokine family members play an important role. This has led to the proposal that NDs are polygenic auto-inflammatory diseases and has fuelled research to further understand the role of IL-1 family members in the pathogenesis of NDs. The aim of this study was to characterise the expression of the IL-1 family members IL-1β, IL-36γ, IL-33 and IL-1R3 (IL-1RaP) in SS. The expression profile of IL-1β, IL-33, IL-36γ and their common co-receptor IL-1R3 was analysed by immunohistochemistry, in situ hybridisation and double immunofluorescence (IF) in healthy control skin (HC) and lesional skin samples of SS. Marked overexpression of IL-1β in the dermis of SS (p < 0.001), and a non-significant increase in dermal (p = 0.087) and epidermal (p = 0.345) IL-36γ expression compared to HC was observed. Significantly increased IL-1R3 expression within the dermal infiltrate of SS skin samples (p = 0.02) was also observed, whereas no difference in IL-33 expression was found between SS and HC (p = 0.7139). In situ hybridisation revealed a good correlation between gene expression levels and the above protein expression levels. Double IF identifies neutrophils and macrophages as the predominant sources of IL-1β. This study shows that IL-1β produced by macrophages and neutrophils and IL-1R3 are significantly overexpressed in SS, thereby indicating a potential pathogenic role for this cytokine and receptor in SS.

Periorbital Necrotizing Sweet's Syndrome: A Case Report

Sweet's syndrome (acute febrile neutrophilic dermatosis) is an uncommon inflammatory condition most often associated with painful skin lesions of the head, neck, and upper extremities. To the authors' knowledge, this case report is the only published record of the necrotizing clinical variant of Sweet's syndrome in the periorbital space. This case follows a 91-year-old female who presented with generalized cutaneous eruptions of tender erythematous plaques, including a necrotic plaque of the left upper eyelid, and pancytopenia. A biopsy of an inner thigh lesion was consistent with Sweet's syndrome. Initially diagnosed with preseptal cellulitis, the patient experienced marked clinical improvement with corticosteroids. This, coupled with the histopathologic findings of her thigh biopsy and the absence of eyelid margins, led to the diagnosis of periorbital necrotizing Sweet's syndrome. Although cases of Sweet's syndrome in the periorbital region are rare, these diagnoses should not be overlooked and may be critical to patient care.

Clinical characteristics, diagnosis and management of Sweet syndrome induced by azathioprine

Sweet syndrome is a rare complication of azathioprine treatment with unelucidated clinical features. The purpose of this study was to investigate the clinical characteristics of azathioprine-induced Sweet syndrome (AISS) and provide a reference for diagnosis, treatment and prognosis. We collected relevant case reports of AISS by searching Chinese and English databases from 1960 to December 31, 2022, extracted the data and carried out a retrospective analysis. The median age of the 44 patients was 50 (range 9-89) years, and they included 32 males (72.7%). Fever (86.4%) and arthralgia (31.8%) were the most common clinical symptoms. The skin lesions were mainly pustules (54.5%), papules (40.9%), plaques (40.9%) and nodules (31.8%), which were mainly distributed on the extremities (54.5%), face (38.6%) and hands (36.4%). Laboratory examination revealed neutropenia (65.9%) as well as elevated C-reactive protein (63.6%) and erythrocyte sedimentation (40.9%) rates. Histopathology of the lesioned skin showed neutrophil infiltration (93.2%) and dermal edema (38.6%). Symptom relief was achieved at a median time of 7 days (range 2-28 days) after azathioprine discontinuation in all patients. Nine patients (20.5%) had skin lesions that recurred within 24 h after taking azathioprine again. Clinicians and pharmacists should grasp the regularity and characteristics of AISS and should not recommend the readministration of azathioprine, to avoid the recurrence of Sweet syndrome.

Unique challenges to diagnosing sweet syndrome following induction chemotherapy for relapsed Acute Myeloid Leukemia (AML): A case and brief-review

Background

Sweet Syndrome (SS) is a rare inflammatory skin condition characterized by the sudden appearance of tender, erythematous or violaceous papules, plaques, and nodules typically found on the face, neck, shoulder, upper extremities, and trunk. Often, SS is difficult to diagnose because of its various non-specific manifestations, including fever, arthralgia, myalgia and ocular involvement. In most cases described in literature, cutaneous and pulmonary symptoms of SS present in a concomitant manner. Several reported cases of pulmonary SS have shown that if left untreated, acute respiratory distress syndrome can ensue and progress to fatal respiratory failure.

Case report

A 58-year-old female with acute myeloid leukemia (AML) secondary to chronic lymphocytic leukemia (CLL) presented with new nodular lesions, dyspnea, and fevers. Chest X-ray revealed pulmonary infiltrates. The patient developed new facial lesions and worsening hypoxic respiratory failure. Further infectious workup was negative. She was found to have SS with pulmonary involvement and initiated on high-dose intravenous (IV) steroids with marked clinical improvement.

Conclusions

Major and minor criteria for the diagnosis of lung-associated SS should be carefully evaluated, especially when a biopsy is unavailable. The following case report describes the clinical course and outcomes from treatment for this patient.

Immune Reactions in Major Types of Oncological Treatment

In recent years, there has been a noticeable development in oncological treatment, including chemotherapy and biological treatment. Despite their significant effectiveness, they are not free from side effects, such as allergic and dermatological reactions. These reactions can vary in severity and outcome, including potential death. Examples, among others, are type I-IV hypersensitivity reactions of various origins and skin reactions including rashes, itching and redness, but also severe cutaneous syndromes. Due to the therapy used, these may include Stevens-Johnson syndrome, toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptoms, drug-induced hypersensitivity syndrome and acute generalized exanthematous pustulosis. In some cases, it is necessary to interrupt therapy, which may result in a poorer outcome and shorten the patient's survival. This paper reviews various types of research documents published since 2016. It aims to systematize the latest knowledge and highlight the need for further research into ways to avoid adverse reactions.

The Role of Sex and Gender in Dermatology - From Pathogenesis to Clinical Implications

BACKGROUND

Sex and gender have increasingly been recognized as significant risk factors for many diseases, including dermatological conditions. Historically, sex and gender have often been grouped together as a single risk factor in the scientific literature. However, both may have a distinct impact on disease incidence, prevalence, clinical presentation, severity, therapeutic response, and associated psychological distress.

OBJECTIVES AND PROJECT DESCRIPTION

The mechanisms that underlie differences in skin diseases between males, females, men, and women remain largely unknown. The specific objectives of this review paper are:To highlight the biological differences between males and females (sex), as well as the sociocultural differences between men and women (gender) and how they impact the integumentary system.To perform a literature review to identify important sex- and gender-related epidemiological and clinical differences for various skin conditions belonging to a range of disease categories and to discuss possible biological and sociocultural factors that could explain the observed differences.To discuss dermatological skin conditions and gender-affirming treatments within the transgender community, a population of individuals who have a gender identity which is different than the gender identity they were assigned at birth.

FUTURE IMPACT

With the rising number of individuals that identify as non-binary or transgender within our increasingly diverse communities, it is imperative to recognize gender identity, gender, and sex as distinct entities. By doing so, clinicians will be able to better risk-stratify their patients and select treatments that are most aligned with their values. To our knowledge, very few studies have separated sex and gender as two distinct risk factors within the dermatology literature. Our article also has the potential to help guide future prevention strategies that are patient-tailored rather than using a universal approach.

Atypical Sweet syndrome: skin sinus tracts in an acutely febrile patient after lymphoma treatment: a case report

Sweet syndrome (SS) is an uncommon inflammatory disease that involves painful skin, edematous, red papules, plaques, or nodules often accompanied by fever and leukocytosis. SS has three subtypes, including classical, malignant-tumor associated, and drug-induced SS (DISS). Patients with DISS have clear histories of recent drug exposure. The incidence of SS is high in hematological malignancy but rare in lymphomas. Glucocorticoid treatment is the recommended treatment for all subtypes of SS. This case study describes a male patient who had a history of sALCL(Systemic anaplastic large cell lymphoma) and was treated with multiple cycles of monoclonal-antibody (mAb) therapy. They also received the G-CSF injection at the site where skin lesions later developed. They met the diagnosis criteria for DISS, which was considered to be caused by the G-CSF injection. In addition, BV(Brentuximab vedotin) administration might predispose them to DISS. This case illustrates the first reported SS during the lymphoma treatment, with rare clinical presentations of local crater-like suppurative skin lesions. This case expands the available literature on SS and hematologic neoplasms and reminds clinicians to promptly recognize and diagnose SS to minimize patient morbidity and long-term sequelae.

Sweet syndrome unresponsive to corticosteroid therapy managed with ayurveda medication: A case report

BACKGROUND

Sweet syndrome (SS) is characterized by sudden appearance of multiple, painful erythematous, papular-nodular skin lesions accompanied by a fever and myalgia. SS resembles Visphota (Bullous eruption disorders) in Ayurveda. SS is a scarcerare skin condition, and Ayurvedic management of this condition is not reported. Therefore, this case report is prepared after taking informed consent from the patient.

CASE PRESENTATION

A 34-year-old male patient presented with a complaint of the appearance of multiple blisters over the upper and lower extremities, forehead, and chest with mild fever, congestion of the eye, joint pain, and muscular stiffness for the last two weeks. He has been on oral prednisolone for ten weeks by a dermatologist. The patient has no history of taking drugs in the previous four months before the onset of the skin lesions. The patient was prescribed Nagaradi Kasya (Amrttam Kasaya), Siddha Makardwaja (Plain), Kaisara Guggulu (KG), Ashwagandha ghana vati, and Avipatikar Churna in recommended dose for two weeks. Fifty percentage lesions disappear along systemic symptoms within seven days and complete remission of lesions in fifteen days. The medication was stopped after fifteen days and observed for one year. There is a significant reduction of inflammatory markers like-erythrocyte sedimentation rate (ESR), Total Leucocyte Count (TLC), and C Reactive protein (CRP) after the treatment compared to the baseline also.

CONCLUSION

Ayurvedic modalities may be a better treatment option in rare skin conditions like sweet syndrome, where corticosteroid usage failed to improve. More evidence of the usefulness of the Ayurvedic therapeutic approach must be gathered.

Sweet Syndrome Associated with Myelodysplastic Syndrome-A Review of a Multidisciplinary Approach

Sweet syndrome (SS) is a rare disease described as a febrile neutrophilic dermatosis with acute onset, the pathogenesis of which has not yet been elucidated. The syndrome is characterized by the sudden onset of erythematous infiltrated papules or plaques located on the upper body and is associated with fever, leukocytosis and neutrophilia. The lesions show a dense dermal infiltration with mature neutrophils. The condition is responsive to systemic steroids. The central nervous system, bones, muscles, eyes, ears, mouth, heart, lung, liver, kidneys, intestines, and spleen may be affected by SS as extracutaneous manifestations. More and more cases have been found to be associated with malignancies, particularly myelodysplastic syndrome, and, less frequently, other hematologic malignancies or solid tumors. Approximately 21% of patients with SS have an associated malignancy and up to 80% of MASS cases are associated with hematological diseases, predominantly myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). Myelodysplastic syndrome is a clonal disease of the bone marrow characterized by inefficient hematopoiesis, dysplasia of the bone marrow and peripheral cytopenias. Affected patients have a high risk of leukemic transformation. After analyzing later studies and current practical aspects regarding MDS-related SS, we suggest an algorithm for evaluating these patients.

A Case of Neutrophilic Dermatoses-Sweet’s Syndrome Coexisting with SAPHO Syndrome

SAPHO (synovitis, acne, pustulosis, hyperostosis, osteitis) syndrome is a rare disease characterized by osteoarticular and cutaneous manifestations. SAPHO syndrome mostly involves the skin, mainly presented as palmoplantar pustulosis and severe acne. Sweet's syndrome (SS) is a neutrophilic dermatosis of unknown cause, which may be caused by autoinflammation. So far, SAPHO syndrome complicated with SS has been rarely reported worldwide. Here, we present a rare case diagnosed in our hospital with detailed clinical information. This patient presented pain and swelling in her right leg. Later, she developed red papules on her right lower eyelid and a skin biopsy showed diffuse lymphocytic and neutrophilic infiltration in the superficial dermis. She was diagnosed with SAPHO syndrome and SS according to medical history and examination. These two diseases share parts of autoinflammatory signaling pathways and might be different variations of the spectrum of autoinflammatory diseases. Through this case, we aim to provide a new horizon for the regulation of neutrophils in SAPHO syndrome and skin lesions like SS.

Evaluation of Delayed-Type Hypersensitivity to Antineoplastic Drugs-An Overview

Nowadays, clinical practice encounters the problem of delayed-type hypersensitivity (DTH) induced by several drugs. Antineoplastic treatments are among the drugs which show an elevated proportion of DHT reactions, leading to the worsening of patients' quality of life. The range of symptoms in DHT reactions can vary from mild, such as self-limiting maculopapular eruptions, to severe, such as Stevens-Johnson Syndrome. The development of these reactions supposes a negative impact, not only by limiting patients' quality of life, but also leading to economic loss due to market withdrawal of the affected drugs and high hospitalization costs. However, despite this problem, there are no available standard in vitro or in vivo methods that allow for the evaluation of the sensitizing potential of drugs in the preclinical phase. Therefore, the aim of this review is to summarize the skin reactions caused by the different antineoplastic families, followed by a comprehensive evaluation of the in vitro and in vivo methods used to detect DTHs and that could be suitable to test antineoplastic hypersensitivity reactions.

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.

Identification of a neutrophil-specific PIK3R1 mutation facilitates targeted treatment in a patient with Sweet syndrome

BackgroundAcute febrile neutrophilic dermatosis (Sweet syndrome) is a potentially fatal multiorgan inflammatory disease characterized by fever, leukocytosis, and a rash with a neutrophilic infiltrate. The disease pathophysiology remains elusive, and current dogma suggests that Sweet syndrome is a process of reactivity to an unknown antigen. Corticosteroids and steroid-sparing agents remain frontline therapies, but refractory cases pose a clinical challenge.MethodsA 51-year-old woman with multiorgan Sweet syndrome developed serious corticosteroid-related side effects and was refractory to steroid-sparing agents. Blood counts, liver enzymes, and skin histopathology supported the diagnosis. Whole-genome sequencing, transcriptomic profiling, and cellular assays of the patient's skin and neutrophils were performed.ResultsWe identified elevated IL-1 signaling in lesional Sweet syndrome skin caused by a PIK3R1 gain-of-function mutation specifically found in neutrophils. This mutation increased neutrophil migration toward IL-1β and neutrophil respiratory burst. Targeted treatment of the patient with an IL-1 receptor 1 antagonist resulted in a dramatic therapeutic response and enabled a tapering off of corticosteroids.ConclusionDysregulated PI3K/AKT signaling is the first signaling pathway linked to Sweet syndrome and suggests that this syndrome may be caused by acquired mutations that modulate neutrophil function. Moreover, integration of molecular data across multiple levels identified a distinct subtype within a heterogeneous disease that resulted in a rational and successful clinical intervention. Future patients will benefit from efforts to identify potential mutations. The ability to directly interrogate the diseased skin allows this method to be generalizable to other inflammatory diseases and demonstrates a potential personalized medicine approach for patients with clinically challenging disease.Funding SourcesBerstein Foundation, NIH, Veterans Affairs (VA) Administration, Moseley Foundation, and H.T. Leung Foundation.

Bullous Sweet syndrome as a presentation of chronic myelogenous leukaemia

A woman in her 40s presented with a 3-month-long history of fever and tender erythematous bullous skin lesions not responsive to antibiotics. There had been no previous gastrointestinal, respiratory or urinary infection, nor did she have any history of autoimmune disease, drug reaction or vasculitis.Histological evaluation of skin biopsy showed diffuse dense neutrophilic infiltrates located in dermis diagnostic of Sweet syndrome. Haematological investigations showed leucocytosis with circulating immature cells, which on further investigations with bone marrow biopsy, were evident of chronic myelogenous leukaemia in the accelerated phase. Sweet syndrome was the presenting characteristic of chronic myelogenous leukaemia in this case, which is a rare association. Investigating unusual skin lesions can aid in the suspicion of underlying cancer, allowing for prompt action.

Sweet Syndrome Imitating Cutaneous Cryptococcal Disease

Cryptococcoid Sweet syndrome is a rare histologic variant of the neutrophilic dermatosis presenting clinically with skin lesions typical of classical Sweet syndrome but with yeast-like structures suggestive of Cryptococcus on histopathology. Histochemical stains for fungus and cultures are negative whereas staining for myeloperoxidase is positive. We present 2 cases of cryptococcoid Sweet syndrome with atypical skin manifestations, including hemorrhagic bullae and plaques, and provide a brief review of the literature. Clinicians should be aware that this variant of Sweet syndrome can present with uncommon clinical findings and has histopathologic findings suggestive of Cryptococcus species.

Histiocytoid giant cellulitis-like Sweet syndrome at the site of sternal aspiration: A case report and review of literature

BACKGROUND

Giant cellulitis-like Sweet syndrome (SS) is a rare subtype of SS, and reports of the combined histiocytoid type of pathology are scarce. Here, we report a case of SS with distinctive clinical presentations and which was difficult to distinguish from cellulitis. By sharing this case and a discussion of the related literature in detail, we aim to provide clinicians with new insights into the characteristics of histiocytoid giant cellulitis-like (HGC)-SS and the pathogenesis of SS.

CASE SUMMARY

A 52-year-old male was admitted after experiencing progressive fatigue for 1 mo and tongue swelling with pain for 1 d. He was diagnosed with myelodysplastic syndrome (MDS) and angioneurotic edema of the tongue and floor of the mouth. However, 7 d after examination by sternal aspiration, a violaceous, tender, and swollen nodule developed at the site, with poorly demarcated erythema of the surrounding skin. Considering his profile of risk factors, the diagnosis of cellulitis was made and he was administered broad-spectrum antibiotics. When the lesion continued to worsen and he developed chills and fever, pathogenic and dermatopathological examination led to the diagnosis of HGC-SS. Treatment with prednisone led to the fever being relieved within 24 h and the skin lesion being resolved within 1 wk. The patient refused intensive treatment and was instead given thalidomide, erythropoietin, stanozolol, and supportive care. The prednisone was gradually tapered, with no signs of recurrence, but he died 2 mo later of severe pneumonia.

CONCLUSION

HGC-SS demonstrates unique manifestation. SS and leukemia cutis share cytological origin. Myelofibrosis and SS are adverse prognostic factors for MDS.