Orchitis (Inflammation of the Testicle) in Dogs


Overview of Canine Orchitis

Orchitis is an inflammatory condition of the testes or testicles that can occur in dogs. It may involve one (unilateral) or both (bilateral) testicles and is often associated with epididymitis, which is inflammation of the epididymis, since the two structures are so closely related.

In dogs, orchitis is commonly caused by a bacterial infection where the bacteria enter the testes via the urine, prostatic secretions, blood, mucus membranes or trauma like a puncture wound. Other infectious agents that have been reported to cause orchitis include canine distemper virus, fungal infections (blastomycosis and coccidiomycosis) and tick borne diseases (ehrlichiosis and Rocky Mountain spotted fever).

Trauma to the testicles can also cause an immune mediated orchitis, lymphocytic orchitis, where the body’s own immune system causes the inflammation, and testicular damage.

Orchitis may occur rapidly (acute) or may develop slowly with time (chronic). Intact male breeding dogs or intact male dogs that are allowed to roam free are at increased risk for developing orchitis. Older intact male dogs with a history of chronic prostatic or urinary tract infections are also at risk, as infection can spread into the testicles.

What to Watch For

Symptoms of Orchitis in Dogs may include: 

  • Swelling of one or both of the testicles
  • Testes that feel warm and firm to the touch
  • Excessive licking sometimes with associated skin abrasions
  • Reluctant to move or walking stiffly
  • Loss of appetite
  • Fever
  • Infertility
  • Diagnosis of Orchitis in Dogs

    A complete physical examination including the palpation of the testicles and prostate is essential. Additional tests may include:

  • Complete blood count (CBC)
  • Biochemical profile
  • Urinalysis with culture and sensitivity
  • Brucella canis serum titers
  • Blood cultures
  • Fungal serology titers
  • Cytology (microscopic analysis) and culture of semen
  • Testicular aspirate (inserting a needle into the testes and withdrawing a sample of cells via suction with a syringe) with cytology and culture
  • Scrotal ultrasound
  • Biopsy or castration with histopathology (the microscopic evaluation of a tissue sample)
  • Treatment of Orchitis in Dogs

  • Antibiotic therapy
  • Intravenous fluids
  • Anti-inflammatory medication or analgesics (medication for pain relief)
  • For immune mediated disease, immunosuppressive drugs (drugs that suppress the immune response), such as prednisone are indicated
  • Cold compresses
  • Castration
  • Anti-fungal medication
  • Home Care and Prevention

    If your dog was neutered, the incision should be checked daily for any sign of swelling or discharge. The scrotal sack may be slightly swollen post-operatively, but the swelling should slowly resolve within a week or two. If skin sutures are used, they should be removed in 7 to 10 days. If your dog begins to lick the area excessively, an Elizabethan collar (a collar designed to prevent licking) may be required.

    Animals that are not neutered should have recheck evaluations.        

    The best prevention for orchitis is castration at an early age.

    In-depth Information on Orchitis in Dogs

    Dogs with orchitis present with different clinical signs depending on whether it is an acute (sudden) or chronic (developing slowly over time) condition. Dogs with acute orchitis are usually very painful and act ill. If the orchitis is caused by a bacterial infection, it can lead to septicemia, which is the spread of bacteria into the blood, and which can be life threatening. Testicular abscesses can also form with severe orchitis. Abscesses can become very large and may even break through the skin of the scrotum.

    In dogs the most common cause of acute orchitis is infection caused by the bacteria Brucella canis. Other bacteria that can cause orchitis include Staphylococcus, Streptococcus, Escherichia coli, Proteus and Mycoplasma. Sometimes, the bacterial infection occurs slowly, but it is progressive and leads to a scarring of the testicles and infertility. This chronic orchitis is more difficult to diagnose since many animals feel fine, are not painful and have no clinical signs.

    Immune-mediated orchitis is also a chronic condition that may occur after trauma, or infection. It occurs once the barrier between the blood and testicular tissue is disrupted. An immune response to the testicle (specifically the animals sperm cells) then causes inflammation and subsequent tissue damage.

    Orchitis may also occur due to urinary tract infections. Infections of the prostate gland (prostatitis) or urinary bladder (cystitis) are common routes of transmission due to their close association with the testes (they are connected via the vas deferens). This can lead to either acute or chronic disease. Other diseases that cause similar symptoms as orchitis include:

  • Testicular torsion. A testicular torsion is a twisting of the testicle around the spermatic cord, the structure that leads from the abdomen to the testicle and supplies blood to the testicle. This causes the obstruction of blood flow and subsequent testicular enlargement. Testicular necrosis (death of tissue) may even occur. The entire scrotum may be very swollen and firm. A torsion happens very quickly and is extremely painful.
  • Testicular tumors. Tumors of the testicle are very common and may be confused with either acute or chronic orchitis. Large painful tumors may seem like the acute disease. Smaller multiple, non-painful masses might be mistaken for the chronic disease.
  • Testicular trauma. Blunt trauma to the testicle may cause bleeding within the scrotum leading to an acute swelling. Many times the swelling will resolve on its own, without any therapy.
  • Scrotal hernia. A scrotal hernia occurs when abdominal organs or fat slide through the abdominal wall and enter the scrotum. This causes a scrotal swelling. These hernias may be congenital or traumatic.
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