From the Guidelines
Sweet syndrome is a rare inflammatory skin condition characterized by tender, red inflammatory nodules or papules, usually affecting the upper limbs, face or neck, and is often associated with underlying conditions such as inflammatory bowel disease (IBD) 1. The condition is part of the group of acute neutrophilic dermatoses and can be distinguished by its appearance, distribution, and histological features. It has a strong predilection for women and patients with colonic involvement and other extraintestinal manifestations. Some key points about Sweet syndrome include:
- It is often associated with active disease, particularly in patients with IBD 1
- The rash is mostly associated with active disease and can be triggered by certain medications
- Systemic corticosteroids have been reported to be effective in treating Sweet syndrome, with oral prednisone being a common first-line therapy 1
- Alternative treatments may include colchicine, dapsone, or potassium iodide, and in severe or recurrent cases, medications like cyclosporine, methotrexate, or biologics might be necessary The exact trigger mechanism of Sweet syndrome remains unclear, but it is thought to be caused by an abnormal immune response leading to neutrophil infiltration in the skin. It is worth noting that while Sweet syndrome can be associated with various underlying conditions, including certain cancers, the provided evidence does not support a strong link between Sweet syndrome and leukemia treatment, such as nilotinib 1.
From the Research
Definition and Characteristics of Sweet Syndrome
- Sweet syndrome (SS) is an infrequent skin disease characterized by sudden onset of fever, leukocytosis, neutrophilia, and tender erythematous plaques infiltrated by neutrophils 2.
- It is also known as acute febrile neutrophilic dermatosis, and is characterized by pyrexia, elevated neutrophil count, painful red papules, nodules, plaques, and an infiltrate consisting predominantly of mature neutrophils 3.
- The syndrome presents with a constellation of clinical symptoms, physical features, and pathologic findings, including fever, neutrophilia, tender erythematous skin lesions, and a diffuse infiltrate of mature neutrophils in the upper dermis 4.
Clinical Settings and Associations
- Sweet syndrome can be classified into three clinical settings: classical (or idiopathic), malignancy-associated, and drug-induced 3, 4.
- Classical Sweet syndrome usually presents in women between 30 to 50 years old, and may be associated with inflammatory bowel disease and pregnancy 4.
- Malignancy-associated Sweet syndrome can occur as a paraneoplastic syndrome in patients with an established cancer or previously undiscovered cancer 4.
- Drug-induced Sweet syndrome most commonly occurs in patients treated with granulocyte-colony stimulating factor, but other medications may also be associated with it 4.
Pathogenesis and Treatment
- The pathogenesis of Sweet syndrome may be multifactorial and remains to be definitively established, but clinical and laboratory evidence suggests that cytokines have an etiologic role 4.
- Systemic corticosteroids are the therapeutic gold standard for Sweet syndrome, with prompt response and dramatic improvement of symptoms and skin lesions 2, 3, 4.
- Other treatment options include topical and intralesional corticosteroids, potassium iodide, colchicine, indomethacin, clofazimine, cyclosporine, and dapsone 3, 4.
- Spontaneous resolution of symptoms and lesions can occur, but recurrence may follow either spontaneous remission or therapy-induced clinical resolution 4.