Orchitis and epididymitis are sometime happen together. Adult orchitis is caused by epididymitis directly spreading to the testicles or menstrual blood. The following are the specific differences between the two diseases: The cause is different. orchitis is caused by bacteria. It most caused by epididymitis directly spreading to the testicles. Acute orchitis in children is usually caused by mumps virus. Epididymitis is due to the delayed urinary tract and bacterial infection, causing the bacteria to enter the epididymis through the vas deferens lumen. Different inspection methods. Orchitis: Orchitis is similar to epididymitis, but the testicular redness is not so obvious. It can be clearly seen that the unilateral or bilateral testicular are swelling, people feel pain if press testicular, the scrotal skin is also obviously red and swollen, and there is a sense of heat. Epididymitis: The patient's entire scrotum is red and hot, sensitive to touch, and burning when urinating. The scrotum is painful, but the symptoms are relieved when patients rest in bed. Different methods of care. Orchitis: Because severe orchitis is easy to make men lose fertility, doctors might use antibiotics and painkillers; patients also need cold compress on testicles. If patients of orchitis in acute phase is not treated properly, bacterial orchitis can form an abscess or evolve into chronic orchitis. Epididymitis: Treatment of epididymitis should take appropriate antibiotics to relieve acute pain; then cold compress on testicles, while patients should make testicles raised, they can use the rolled up socks under testicles.