Abstract
Prurigo pigmentosa is an inflammatory dermatosis that was first described by Nagashima et al. in 1971. The lesions are characterized by recurrent pruritic erythematous papules that resolve leaving a peculiar, reticulate hyperpigmentation. The cause of prurigo pigmentosa is unknown, however, some cases with prurigo pigmentosa have been reported to be related to ketosis. We report here three patients with PP that were seen during the onset of diabetes mellitus with diabetic ketosis. These males aged 15, 12 and 41years complained of thirst, polyurea and weight loss. From the laboratory examinations on their admission revealing ketosis (ketoacidosis in the seccond patient), hyperglycemia and decreased insulin secretion, they were diagnosed as having newly onset-diabetes. They had HLA-DR 4. During the onset period, prurigo pigmentosa was found on the right shoulder, the neck and back and the upper abdomen of the respective patients. In all the patients, pruritic eruption improved after intensive insulin treatment and only patient 3 was treated with minocycline. We suggest that ketosis caused by newly onset-diabetes and HLA-DR 4 may play a potential role in the pathogenesis of prurigo pigmentosa.
