Epidemiological Study of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis throughout Japan

Abstract

An epidemiological study of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) throughout Japan from 2005 to 2007 was performed using registration forms. A total of 370 cases (258 cases of SJS and 112 cases of TEN) were included. The prevalence per million per year was 3.1 for SJS, 1.3 for TEN, and 4.4 for SJS plus TEN. The relative SJS to TEN ratio was 1 : 2.3. A small peak in the fourth and a large peak in the seventh decade of life were observed. The male to female ratio of SJS was 1 : 1.14, whereas that of TEN was 1 : 0.95. The mortality rate of SJS was 3%, but that of TEN was 19%.The most frequently suspected agents were antibiotics and nonsteroidal antiinflammatories (NSAIDs). The period from the start of anticonvulsant treatment to the onset of the rash was significantly longer than that of antibiotic treatment. The mean severity score of SJS was 5.0±2.0, whereas that of TEN was 8.3±2.7; the difference was statistically significant. Eye involvement was documented in 77% of TEN patients but in only 26% of SJS patients. Mucous membrane involvements, such as lip erosion with bloody crusting, extensive oral cavity erosion, genital erosion, and pulmonary mucous membranes was significantly more frequent in TEN than in SJS patients. Histological findings, including apoptosis and necrosis throughout the epidermis, were significantly less frequent in SJS than in TEN patients. This is the first epidemiological study of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) throughout Japan.