Orchitis is infection and inflammation of the testicles; it's common in male dogs. It's generally caused by injury or trauma to the scrotum, such as a bites or a burn. Bacteria enter the wound and spread throughout the spermatic ducts from the bladder or prostate; then infection sets in.
Most of the symptoms of orchitis are localized -- swollen testicles, scrotal skin irritation and soreness are the most common symptoms. You may notice your dog excessively licking his scrotal area. Non-localized symptoms may include lethargy, fever and appetite loss. Males with orchitis are often infertile or become infertile.
Treatment options vary depending on severity of condition. Applying cold packs to the scrotum may help reduce swelling, but your veterinarian may want to start a course of antibiotics, corticosteroids or nonsteroidal anti-inflammatory drugs. For severe cases or cases whereby the testicles have become small and firm, neutering may become the best treatment.