Sweet's syndrome is a rare skin condition. Its main signs include fever and painful skin lesions that appear mostly on your arms, neck, head and trunk.

The exact cause of Sweet's syndrome isn't known. In some people, it's triggered by an infection, illness or certain medications. Sweet's syndrome can also occur with some types of cancer.

The most common treatment for Sweet's syndrome is corticosteroid pills, such as prednisone. Signs and symptoms often disappear just a few days after treatment begins, but recurrence is common.