What Is Sweet’s Syndrome?

Sweet's syndrome is a rare condition that involves a painful rash, typically along with a fever. The rash erupts mostly on the skin of the arms, neck, face, and trunk. The cause of Sweet's syndrome isn't fully known, but there are several typical scenarios in which it is known to occur.

In some people, it seems to be triggered by an infection, and it can be associated with inflammatory bowel disease or pregnancy. It may be associated with cancer, most commonly acute myelogenous leukemia, and there is also a drug-induced form of Sweet’s syndrome.

Sweet’s syndrome may go away on its own, but it is commonly treated with corticosteroid pills, such as prednisone. Sweet's syndrome is also known as acute febrile neutrophilic dermatosis or Gomm-Button disease.

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Symptoms

Sweet's syndrome is marked by the following symptoms:

• Fever
• Small red bumps on your arms, neck, face, or trunk that grow quickly, spreading into painful clusters up to an inch or so in diameter
• A rash may appear abruptly after a fever or upper respiratory infection.

Types of Sweet's Syndrome

The condition is identified by three different types:

Classical

• Usually in women aged 30 to 50 years
• Often preceded by an upper respiratory tract infection
• May be associated with inflammatory bowel disease and pregnancy
• About 1/3 of patients have a recurrence of the Sweet’s syndrome

Malignancy-Associated

• Can occur among people who already known to have cancer
• Can occur with blood cancer or solid tumor that was previously undiscovered
• Most commonly related to acute myelogenous leukemia, but other cancers possible, such as breast or colon

Drug-Induced

• Most commonly occurs in patients who have been treated with granulocyte-colony stimulating factor given to boost white blood cells
• Other medications may also be associated; drugs linked to Sweet's syndrome include azathioprine, certain antibiotics, and some nonsteroidal anti-inflammatory drugs

Involvement Outside the Skin

Owing to the rarity of Sweet’s syndrome, limited data, and multiple possible underlying conditions, not all of the findings linked to this disorder are necessarily from the syndrome itself.

That said, Sweet’s syndrome is thought to potentially involve other tissues and organs, in addition to the skin. The involvement of the bones and joints has been documented, as has the involvement of the central nervous system — a “neuro-Sweet disease” that has been described.

The eyes, ears, and mouth can also be affected.

• Tender red bumps can extend from the external ear, into the canal and eardrum.
• The eyes can be involved, with swelling, redness, and inflammation.
• Sores on the tongue, inside the cheeks, and on the gums may develop.
• Inflammation and/or enlargement of internal organs of the abdomen and chest has also been reported.

Risk Factors

Sweet's syndrome is very rare, so its risk factors are not as well developed as they might be for some other illnesses. In general, women are more likely to have Sweet's syndrome than are men, and, although older adults and even infants can develop Sweet's syndrome, people between the ages of 30 and 60 are the main affected age group.

Additionally, the conditions that define the types listed above may be considered risk factors.

Sweet's syndrome is sometimes associated with cancer, but not everyone with Sweet’s syndrome has cancer. In a study with 448 people with Sweet’s syndrome, only 21 percent (or 96 of 448 individuals) were found to have either a hematologic malignancy or a solid tumor. Of note, however, is that Sweet’s syndrome can sometimes lead to the discovery of unknown cancer — and also that the recurrence of malignancy-associated Sweet's syndrome can signal a relapse of cancer.

The condition may be associated with sensitivity to certain drugs, it may follow an upper respiratory infection (and many people report having flu-like symptoms before the rash appears) and it can also be associated with inflammatory bowel disease, which includes Crohn’s disease and ulcerative colitis. Some women have developed Sweet's syndrome during pregnancy as well.

Diagnosis

Sweet's syndrome might be suspected or recognized by examining the rash. A variety of tests are often necessary to make the diagnosis and/or rule out other causes.

A sample of your blood may be sent to a laboratory to look for an unusually large number of white blood cells and/or the presence of blood disorders.

Skin biopsy, or removal of a small piece of the affected skin for examination under a microscope, may be performed. Sweet's syndrome has characteristic abnormalities: inflammatory cells, mostly mature white blood cells of the neutrophil type, infiltrate and are typically located in an upper layer of the living part of the skin. Of note, infectious agents can produce similar findings in the skin, so the sample is sometimes tested for bacteria, fungi, and viruses.

The most consistent laboratory findings in patients with Sweet's syndrome are elevated white blood cells and neutrophils in the bloodstream and an elevated erythrocyte sedimentation rate, or ESR. That said, an elevated white blood cell count is not always seen in all patients with biopsy-confirmed Sweet's syndrome.

Treatment

Sweet's syndrome may go away on its own, without any treatment, however, treatments are effective and generally work quickly. Untreated, the rash can last for weeks to months. The most common medications used for Sweet's syndrome are corticosteroids. Oral corticosteroids, such as prednisone, may be used, especially if you have more than a few areas of skin affected. These medications are systemic, meaning they go throughout the whole body and not just the skin.

Other forms of steroids such as creams or ointments are sometimes used for smaller, less widespread rashes. When a person with Sweet’s syndrome doesn’t tolerate systemic corticosteroids or has side effects with long-term corticosteroids, there are other medications that might be used, such as dapsone, potassium iodide, or colchicine.

Patients with Sweet's syndrome may develop complications due to skin involvement, the Sweet's syndrome-associated conditions, or both. Antimicrobial therapy may be used if the skin sores from the rash are at risk of becoming secondarily infected.

Attention to any Sweet's syndrome-associated conditions may also be an important part of the treatment of Sweet's syndrome, itself. For instance, the symptoms associated with the syndrome sometimes remit with treatment or cure of the underlying malignancy.

A Word From Verywell

Medications such as corticosteroids may provide relief from the syndrome, but attention to the underlying associated conditions may also be important. If you have the drug-induced type of Sweet’s syndrome, once the causative drug has been discontinued, the disease typically, but not always, improves and spontaneously remits.