Sweet syndrome is a rare skin disorder characterized by fever, inflammation of the joints (arthritis), and the sudden onset of a rash. The rash consists of bluish-red, tender papules that usually occur on the arms, legs, face or neck, most often on one side of the body (asymmetric). In approximately 80 percent of cases, Sweet syndrome occurs by itself for no known reason (idiopathic). In 10 to 20 percent of cases, the disorder is associated with an underlying malignancy, usually a hematologic malignancy such as certain types of leukemia. The exact cause of Sweet syndrome is unknown.
The major symptom of Sweet syndrome is the sudden onset of bluish-red, tender papules on the arms, legs, face or neck. These skin lesions may also occur on the thighs and trunk. The lesions are sometimes up to an inch in diameter, flat or slightly elevated, irregularly-shaped, and inflamed. The lesions slowly grow larger and last for at least two weeks. The symptoms of Sweet syndrome often subside but tend to recur chronically.
Individuals with Sweet syndrome also experience fever, a general feeling of ill health (malaise), inflammation and pain of the joints (arthritis and arthralgia). In addition, affected individuals may experience inflammation of the delicate membrane that lines the eyes (conjunctivitis). In some cases, individuals with Sweet syndrome may have lesions affecting the mucous membranes of the mouth (oral mucosa).
In most cases (approximately 80 percent), Sweet syndrome occurs without any underlying disorder. In these cases, the onset of Sweet syndrome usually follows an infection of the upper respiratory tract or gastrointestinal system.
In the remaining 20 percent of cases, Sweet syndrome is associated with a malignancy, most often a malignancy that affects the blood (hematologic malignancies), such as certain types of leukemia and, rarely, cancers of the genitourinary and gastrointestinal tracts.
In some cases, Sweet syndrome may also be associated with autoimmune and inflammatory disorders such as Behcet’s disease, Sjogren’s syndrome, ulcerative colitis or Crohn’s disease. (For more information on these disorders, see the Related Disorders section of this report.)
The exact cause of Sweet syndrome is not known. Some researchers speculate that Sweet syndrome occurs as an allergic reaction to an unknown agent, as a response to an infectious disease, or as a result of contact with certain chemicals (chemical irritants).
According to the medical literature, some cases of Sweet syndrome have occurred after the use of certain drugs, especially granulocyte-monocyte colony stimulating factor.
Patients often have an upper respiratory infection, tonsillitis, or influenza-like illness that precedes their skin lesions by one to three weeks.
Approximately 10 to 20 percent of cases have an associated malignancy. The associated malignancies include leukemias and lymphomas, as well as breast, genitourinary, and gastrointestinal tumors. Sweet syndrome has also been associated with inflammatory states, such as inflammatory bowel disease, toxoplasmosis, salmonellosis, tuberculosis, and vaginal infections. Pregnancy-associated Sweet syndrome typically presents in the first or second trimester. There does not appear to be any fetal risk, and the syndrome may recur with subsequent pregnancies.
Sweet syndrome usually affects females in the fifth and sixth decades of life. However, cases of Sweet syndrome affecting males, children, and infants have been reported. More than 425 cases have been reported in the medical literature.
A diagnosis of Sweet syndrome is made based upon a thorough clinical evaluation, a detailed patient history, identification of classic symptoms, and a variety of specialized tests. In many cases, surgical removal (biopsy) and microscopic examination of small samples of skin tissue may reveal abnormally high levels of a certain white blood cell (neutrophils) in the blood (neutrophilia).
The treatment of Sweet syndrome is directed toward the specific symptoms that are apparent in each individual. In some cases, Sweet syndrome may resolve itself with no treatment. In most cases, treatment with low doses of corticosteroids such as methylprednisolone or prednisone has proven effective in eliminating symptoms. However, Sweet syndrome often recurs periodically despite therapy.
Individuals with Sweet syndrome should receive a thorough clinical examination to detect any possible underlying malignancy or disorder that may be associated with Sweet syndrome, including a complete hematologic evaulation.
Other treatment is symptomatic and supportive.
Alternate drug therapies have been used to treat individuals with Sweet syndrome including indomethacin, potassium iodine, colchicines, cyclosporin, and dapsone. More studies are needed to determine the long-term safety and effectiveness of these drugs for the treatment of Sweet syndrome.
Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.
For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
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