Acute febrile neutrophilic dermatosis in Infant/Neonate
See also in: Cellulitis DDxAlerts and Notices
Synopsis

- Classic idiopathic
- Pregnancy-associated
- Parainflammatory
- Paraneoplastic
- Drug-associated
- Classic (includes all inflammatory causes including infection, inflammatory bowel disease [IBD], and pregnancy)
- Paraneoplastic and drug-related
Sweet syndrome can proceed a diagnosis of malignancy by several months.
Pediatric Sweet syndrome is categorized into:
- Neonatal Sweet syndrome (ages birth to 3 months).
- Infantile Sweet syndrome (ages 3 months to 3 years).
- Junior Sweet syndrome (ages 3-18 years).
Pathergy is seen in up to a third of pediatric patients. Although still a minority of patients, it is slightly more common than in the adult population. When present, lesions will arise or worsen in sites of cutaneous injury, such as needle sticks. Fever may accompany or precede cutaneous involvement. The syndrome frequently includes extracutaneous manifestations such as fever, headaches, myalgias, malaise, arthralgias, and ocular inflammation. Other sites that may rarely be affected include the oral mucosa, liver (hepatitis), kidney (acute renal failure), lungs (pulmonary abscess and infiltrate), heart (pericarditis, aortitis), central nervous system (CNS) (encephalitis), GI tract (ileitis), lymphatics (lymphadenitis), musculoskeletal (myositis), and bones (sterile osteomyelitis). Hypotension and tachycardia are rare but can occur as a result of systemic inflammation.
Although the exact etiology is still unclear, abnormal cytokine expression and atypical neutrophil function are thought to contribute to the pathogenesis. A genetic predisposition may also contribute.
Sweet syndrome typically responds dramatically to systemic corticosteroids, but recurrences can be seen in up to a third of cases.
Codes
ICD10CM:L98.2 – Febrile neutrophilic dermatosis [Sweet]
SNOMEDCT:
84625002 – Acute febrile neutrophilic dermatosis
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Diagnostic Pearls
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Differential Diagnosis & Pitfalls
- Bacterial infections (furunculosis, cellulitis)
- Sporotrichosis
- Mycobacteria spp infections (typical and atypical), including Mycobacterium marinum
- Majocchi granuloma
- Erythema nodosum – Primarily over the shins.
- Acute hemorrhagic edema of infancy
- Pyoderma gangrenosum – Begins as a pustule and evolves into a purulent ulcer with rolled borders. Has similar associations with IBD and malignancy.
- Neutrophilic eccrine hidradenitis – Drug-induced toxicity of the eccrine coils 1-2 weeks following chemotherapy. Palmar involvement is more suggestive of this diagnosis. Patients typically lack fevers, but pathology may be required to differentiate these entities.
- CANDLE syndrome
- Erythema multiforme – Should display classic target lesions with 3 zones of color; favors acral surfaces. Oral involvement is common.
- Bowel-associated dermatosis-arthritis syndrome – Pustular skin lesions and aseptic arthritis in bowel-bypass patients.
- Majeed syndrome – Multifocal osteomyelitis, congenital anemia, and Sweet syndrome-like skin dermatosis.
- Chronic granulomatous disease
- Wells syndrome – Involved skin is typically neither tender nor warm. Eosinophilia is present in 50% of individuals; neutrophilia is unusual. Eosinophils and flame figures can be seen on pathology.
- Drug eruption
- Azathioprine hypersensitivity syndrome – Acute neutrophilic and systemic reaction after initiating azathioprine. See drug-induced hypersensitivity syndrome.
- Urticarial vasculitis
- Erythema elevatum diutinum – A form of necrotizing vasculitis that primarily involves extensor surfaces.
- Cutaneous small vessel vasculitis – Presents symmetrically on the lower extremities; typically smaller than the plaques of Sweet syndrome.
- Behçet disease – Rare, recurrent, and associated with oral or genital ulcers.
- Bromoderma or iododerma
- Leishmaniasis (New World and Old World) – Recent travel to endemic areas.
- Lymphoma / leukemia cutis
- Metastatic carcinoma
- Sarcoidosis
- Orf
- Cat-scratch disease
- Cutaneous anthrax
- Coccidioidomycosis
- VEXAS syndrome
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Management Pearls
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Therapy
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Drug Reaction Data
Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.Subscription Required
References
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Last Reviewed:12/05/2022
Last Updated:02/09/2023
Last Updated:02/09/2023
Acute febrile neutrophilic dermatosis in Infant/Neonate
See also in: Cellulitis DDx