The acute idiopathic scrotal edema (AISE) is a self-limited disease of unknown etiology, characterized by edema and erythema of the scrotum and the dartos, without expansion to the underlying layers of scrotum's wall or to the endoscrotal structures. Boys younger than 10 years old are usually involved in 60-90% of all cases. Diagnosis is made after exclusion of other causes of acute scrotum. We present a case of a 7-year old boy, who was admitted to the Emergency Department due to development of scrotal edema and erythema over the last 48 hours, which extended to the base of the penis. The patient mentioned that he first noticed the erythema on the anterior surface of the right hemiscrotum, which gradually extended. Physical examination did not reveal presence of pathology involving the endoscrotal structures, indicative of need for urgent surgical intervention. Transillumination was negative for blue dot sign. Ultrasonographic examination of the scrotum documented the homogeneity of the testicular parenchyma, while color Doppler revealed the presence of fountain's sign (equal arterial blood supply to both testicles). Conservative strategy was followed and the patient gradually improved within the next three days. In conclusion, meticulous physical examination along with ultrasonographic examination of the suffering scrotum, especially with the highlighting of fountain's sign with color Doppler, document the diagnosis of AISE. Thus, need for urgent surgical investigation of the suffering scrotum due to diagnostic doubt is limited.