Having an inflamed testicle – or orchitis – is a painful experience. Worse, it can affect your fertility. It can affect one or both of your testicles, and has multiple forms and causes.

Gonorrhea, chlamydia and, to a lesser degree, other sexually transmitted diseases can cause bacterial orchitis. This form results from epididymitis, an inflammation of the coiled tube at the back of the testicle that stores and carries sperm. Epididymitis usually is caused by an infection of the urethra or bladder that spreads to the epididymis. Multiple sex partners, or high-risk sexual behavior such as having unprotected sex, will put you at risk of contracting a sexually transmitted disease, and so bacterial orchitis.

You can contract viral orchitis when you get the mumps virus. Viral orchitis affects about a third of all men who contract the mumps after puberty.

An inflamed testicle without either bacterial or viral origin is rare but possible, and known as idiopathic orchitis.

Symptoms of all orchitis forms include:

• Swelling in one or both testicles
• Pain ranging from mild to severe
• Tenderness in one or both testicles, which may last for weeks
• Fever
• Nausea and vomiting

Untreated, orchitis can lead to more severe complications, which may include:

• A shrunken testicle, a condition known as testicular atrophy
• An abscess in the scrotum which fills with pus
• Repeat episodes of epididymitis
• Infertility

To diagnose this condition, expect your doctor to do a physical exam in which she inspects both the inflamed testicle as well as the lymph nodes in your groin. A urinalysis will determine if the orchitis is bacteria-based, and also the sexually transmitted disease that caused it. Ultrasound imaging or a nuclear scan of the testicles (in which a radioactive tracer is inserted into your bloodstream) will rule out testicular torsion, which has similar symptoms.

If your doctor determines that you have bacterial orchitis, she will likely recommend antibiotics. If the bacteria is from a sexually transmitted disease, your partner will need them as well. It can take several weeks of gentle care and ice packs along with the antibiotics before you see any relief.

In the case of viral orchitis, all your doctor can do is address the symptoms. To that end, she will likely prescribe anti-inflammatory meds such as ibuprofen or naproxen.