Abstract
Diaper area dermatitis is a common inflammatory reaction in infants, although it may occur at other ages. One of its severe forms is Sevestre-Jacquet posterosive syphilitic dermatitis, characterized by ulcerated papulo-nodular lesions in areas exposed to urine or feces. We present an atypical case in a nine-year-old boy, an unusual age for the onset of this entity, which is typically seen in infants and young children who use diapers. Initially, child sexual abuse was suspected; however, the diagnosis was confirmed through histopathological examination. This type of dermatitis poses diagnostic challenges when it occurs outside its classic context, warranting careful clinical assessment and complementary studies for proper differentiation.