Sweet's syndrome: diagnostic criteria revisited.

The diagnosis of Sweet's syndrome (SS) is based on a set of criteria that requires the presence of two major and at least two minor criteria. In some cases, however, the diagnosis is not as straightforward due to the absence of certain criteria. The objective of the present study was to review the clinical, histopathological, and laboratory features of the current diagnostic criteria for SS, and to evaluate their validity in the cases reported in the literature as well as in 40 patients treated at our institution. Our comprehensive review of the current criteria for SS reveals that the two major criteria have been consistently present in all cases - including ours - since the first description of SS in 1964. With regard to the minor criteria, on the other hand, there has been marked variability between different studies, and many cases failed to fulfill the requirement of showing two minor criteria. In order to simplify the diagnosis, avoid misdiagnosis, and allow for prompt treatment, we propose two sets of revised diagnostic criteria for SS. The first set comprises constant clinical and histopathological features that must be present and are by themselves sufficient for the diagnosis of SS to be established. The second set includes variable features whose absence does not warrant ruling out SS.