Sweet's syndrome and Pneumocystis carinii pneumonia: two sequelae of low-dose cytosine arabinoside therapy in a patient with acute myeloid leukemia

Lobular neutrophilic panniculitis associated with DNA methyltransferase inhibitors in the treatment of myeloid disease

Cutaneous toxicities to DNA methyltransferase inhibitors are variable and include localized injection site reactions, ecchymoses, maculopapular eruptions, and neutrophilic dermatoses including pyoderma gangrenosum, Sweet syndrome, and neutrophilic eccrine hidradenitis. This series describes two patients diagnosed with lobular neutrophilic panniculitis arising during treatment of acute myelogenous leukemia with "hypomethylating drugs," including the first report of its occurrence with a next-generation agent. Differential diagnoses, histopathologic characteristics, treatment considerations, and proposed pathogenesis will be discussed.

Insights Into the Pathogenesis of Sweet's Syndrome

Sweet's syndrome, also known as Acute Febrile Neutrophilic Dermatosis, is a rare inflammatory condition. It is considered to be the prototype disease of neutrophilic dermatoses, and presents with acute onset dermal neutrophilic lesions, leukocytosis, and pyrexia. Several variants have been described both clinically and histopathologically. Classifications include classic Sweet's syndrome, malignancy associated, and drug induced. The cellular and molecular mechanisms involved in Sweet's syndrome have been difficult to elucidate due to the large variety of conditions leading to a common clinical presentation. The exact pathogenesis of Sweet's syndrome is unclear; however, new discoveries have shed light on the role of inflammatory signaling, disease induction, and relationship with malignancy. These findings include an improved understanding of inflammasome activation, malignant transformation into dermal infiltrating neutrophils, and genetic contributions. Continued investigations into effective treatments and targeted therapy will benefit patients and improve our molecular understanding of inflammatory diseases, including Sweet's syndrome.

Neutrophilic dermatoses: Pathogenesis, Sweet syndrome, neutrophilic eccrine hidradenitis, and Behçet disease

Neutrophilic dermatoses are a heterogeneous group of inflammatory skin disorders that present with unique clinical features but are unified by the presence of a sterile, predominantly neutrophilic infiltrate on histopathology. The morphology of cutaneous lesions associated with these disorders is heterogeneous, which renders diagnosis challenging. Moreover, a thorough evaluation is required to exclude diseases that mimic these disorders and to diagnose potential associated infectious, inflammatory, and neoplastic processes. While some neutrophilic dermatoses may resolve spontaneously, most require treatment to achieve remission. Delays in diagnosis and treatment can lead to significant patient morbidity and even mortality. Therapeutic modalities range from systemic corticosteroids to novel biologic agents, and the treatment literature is rapidly expanding. The first article in this continuing medical education series explores the pathogenesis of neutrophilic dermatoses and reviews the epidemiology, clinical and histopathologic features, diagnosis, and management of Sweet syndrome, neutrophilic eccrine hidradenitis, and Behçet disease.

Sweet's syndrome--a comprehensive review of an acute febrile neutrophilic dermatosis

Sweet's syndrome (the eponym for acute febrile neutrophilic dermatosis) is characterized by a constellation of clinical symptoms, physical features, and pathologic findings which include fever, neutrophilia, tender erythematous skin lesions (papules, nodules, and plaques), and a diffuse infiltrate consisting predominantly of mature neutrophils that are typically located in the upper dermis. Several hundreds cases of Sweet's syndrome have been published. Sweet's syndrome presents in three clinical settings: classical (or idiopathic), malignancy-associated, and drug-induced. Classical Sweet's syndrome (CSS) usually presents in women between the age of 30 to 50 years, it is often preceded by an upper respiratory tract infection and may be associated with inflammatory bowel disease and pregnancy. Approximately one-third of patients with CSS experience recurrence of the dermatosis. The malignancy-associated Sweet's syndrome (MASS) can occur as a paraneoplastic syndrome in patients with an established cancer or individuals whose Sweet's syndrome-related hematologic dyscrasia or solid tumor was previously undiscovered; MASS is most commonly related to acute myelogenous leukemia. The dermatosis can precede, follow, or appear concurrent with the diagnosis of the patient's cancer. Hence, MASS can be the cutaneous harbinger of either an undiagnosed visceral malignancy in a previously cancer-free individual or an unsuspected cancer recurrence in an oncology patient. Drug-induced Sweet's syndrome (DISS) most commonly occurs in patients who have been treated with granulocyte-colony stimulating factor, however, other medications may also be associated with DISS. The pathogenesis of Sweet's syndrome may be multifactorial and still remains to be definitively established. Clinical and laboratory evidence suggests that cytokines have an etiologic role. Systemic corticosteroids are the therapeutic gold standard for Sweet's syndrome. After initiation of treatment with systemic corticosteroids, there is a prompt response consisting of dramatic improvement of both the dermatosis-related symptoms and skin lesions. Topical application of high potency corticosteroids or intralesional corticosteroids may be efficacious for treating localized lesions. Other first-line oral systemic agents are potassium iodide and colchicine. Second-line oral systemic agents include indomethacin, clofazimine, cyclosporine, and dapsone. The symptoms and lesions of Sweet's syndrome may resolved spontaneously, without any therapeutic intervention; however, recurrence may follow either spontaneous remission or therapy-induced clinical resolution.

Sweet's syndrome from an Indian perspective: a report of four cases and review of the literature

BACKGROUND

Sweet's syndrome or acute febrile neutrophilic dermatosis is not frequently reported from India. Four patients fulfilling clinico-pathologic criteria for Sweet's syndrome seen during May-August 2002 prompted us to review reports on Indian patients from the indexed literature.

METHODS

A PubMed and IndMed search for Sweet's syndrome revealed 11 reports appearing between 1985-2002 documenting 12 patients. The clinico-pathologic features, clinical course and treatment of all these 16 patients (including four new cases) were studied.

RESULTS

The study comprised 12 females and four males between 35 days to 57 years of age. There were four children of < 12 years. Ulcerated, crusted lesions in one and typical, erythematous, tender, papulo-nodulo-plaques and targetoid lesions with pseudovesiculation were observed in 13 other patients particularly involving head, neck and upper limbs. Extracutaneous Sweet's syndrome manifesting as gingival hyperplasia and myositis was seen in one patient each. All had simultaneous onset of cutaneous lesions, fever, headache and malaise. Ocular involvement was observed in four patients only. Associated hematoligic disorders recorded were myelodysplasia in three, polycythemia vera in one and leukemia in three patients respectively. Two of these patients had treatment with all-transretinoic acid and low-dose cytosine-arbinoside before onset of Sweet's syndrome. One patient each had symptoms of upper respiratory tract infection and history of minor injury prior to cutaneous lesions. Another patient had pregnancy induced self-limiting Sweet's syndrome. Leukocytosis was present in 11 patients. Three of four new patients had positive tests for antistreptolysin-O and C-reactive protein. Characteristics histologic features were recorded in specimens of all patients. Eleven patients responded to systemic corticosteroids. Colchicin or potassium iodide were effective in one patient each.

CONCLUSION

The overall clinico-pathologic and therapeutic spectrum of Sweet's syndrome in Indian patients does not appear to be different from its established picture.

Sweet's syndrome revisited: a review of disease concepts

Sweet's syndrome, also referred to as acute febrile neutrophilic dermatosis, is characterized by a constellation of symptoms and findings: fever, neutrophilia, erythematous and tender skin lesions that typically show an upper dermal infiltrate of mature neutrophils, and prompt improvement of both symptoms and lesions after the initiation of treatment with systemic corticosteroids. Hundreds of patients with this dermatosis have been reported. The manifestations of Sweet's syndrome in these individuals have not only confirmed those originally described by Dr Robert Douglas Sweet in 1964, but have also introduced new features that have expanded the clinical and pathologic concepts of this condition. The history, clinical characteristics, laboratory findings, associated diseases, pathology, and treatment options of Sweet's syndrome are reviewed. The evolving and new concepts of this dermatosis that are discussed include: (i) Sweet's syndrome occurring in the clinical setting of a disease-related malignancy, or medication, or both; (ii) detection of additional sites of extracutaneous Sweet's syndrome manifestations; (iii) discovery of additional Sweet's syndrome-associated diseases; (iv) variability of the composition and/or location of the cutaneous inflammatory infiltrate in Sweet's syndrome lesions; and (v) additional efficacious treatments for Sweet's syndrome.