Orchitis is an inflammatory condition of the testes or testicles. 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

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

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

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.