Orchitis is inflammation of one or both testicles. It can cause testicular pain, swelling, tenderness, fever, and a general feeling of being unwell. In men’s health, orchitis matters because it can sometimes affect sperm production, fertility, and overall testicular function—especially if it is severe, delayed in treatment, or occurs alongside an infection such as epididymitis. Orchitis may be caused by viruses, bacteria, or sexually transmitted infections, and it should be medically evaluated when symptoms appear suddenly or are intense.
At a glance: orchitis is not just “testicle pain.” It is a medical condition that can overlap with other urgent causes of scrotal pain, including testicular torsion, so prompt assessment is important.
Key takeaways
- Orchitis means inflammation of a testicle, usually causing pain, swelling, and tenderness.
- It may be caused by viral infections such as mumps or by bacterial infection, sometimes linked to a urinary infection or STI.
- Orchitis can involve one testicle or both, and it may occur together with epididymitis (epididymo-orchitis).
- Sudden, severe testicular pain should be treated as urgent because testicular torsion can look similar and needs immediate care.
- Diagnosis may include a physical exam, urine testing, STI testing, and often a scrotal ultrasound.
- Treatment depends on the cause and may include antibiotics, pain relief, scrotal support, rest, and hydration.
- Severe or bilateral orchitis can sometimes affect sperm production, testosterone production, or fertility.
- If symptoms are worsening, recurrent, or associated with a lump, ongoing pain, or fertility concerns, follow-up with a clinician is important.
What is orchitis?
Orchitis is the medical term for inflammation of the testis. The inflammation can be driven by infection or, less commonly, other inflammatory processes. Some people use “orchitis” to describe any inflamed or painful testicle, but medically it refers to an inflamed testicular tissue process rather than every cause of scrotal pain.
Orchitis may develop:
- On its own, although that is less common
- After a viral illness, especially mumps in unvaccinated individuals
- Alongside epididymitis, when the epididymis and testicle are both inflamed
When both the epididymis and testicle are involved, the condition is often called epididymo-orchitis. This is a common real-world presentation and one reason some men are told “orchitis” when there is overlapping swelling and pain in nearby structures.
Alternate names and related terminology
- Testicular inflammation
- Inflamed testicle
- Viral orchitis
- Bacterial orchitis
- Epididymo-orchitis
Why orchitis matters for men’s health and fertility
The testicles are responsible for two major functions: sperm production and testosterone production. Inflammation can disrupt either one, especially if it is severe, prolonged, recurrent, or affects both testicles.
That does not mean every case of orchitis causes infertility or low testosterone. Many men recover fully. But orchitis deserves attention because it can:
- Cause significant pain and interfere with daily activity
- Signal an underlying infection that needs treatment
- Occur with sexually transmitted infections
- Rarely lead to testicular shrinkage (atrophy) after severe inflammation
- Temporarily or, in some cases, more durably affect sperm quality
- Be confused with urgent conditions like torsion or, less commonly, a testicular tumor
For men trying to conceive, a history of orchitis is especially relevant if semen parameters later show low sperm count, reduced motility, or abnormal morphology.
Causes of orchitis
Orchitis is most often caused by infection. The major categories are viral and bacterial.
Viral orchitis
The classic cause is mumps orchitis. Mumps is much less common in vaccinated populations, but it still occurs. Orchitis can appear after the swelling of the salivary glands or as part of the wider illness. Mumps orchitis is more common after puberty than in young boys.
Other viruses may also be associated with testicular inflammation, though mumps is the best-known example.
Bacterial orchitis
Bacterial orchitis often develops when infection spreads from nearby structures, especially the epididymis, urinary tract, or prostate. Common scenarios include:
- Sexually transmitted infections, such as chlamydia or gonorrhea, particularly in sexually active younger men
- Urinary tract bacteria, more common in older men or men with urinary tract obstruction
- Prostatitis or other lower urinary tract infections
- Catheter use or recent urinary instrumentation
Risk factors
Factors that may raise the risk of orchitis or epididymo-orchitis include:
- Recent viral infection
- Unprotected sex or exposure to an STI
- History of urinary tract infection
- Prostate enlargement or difficulty emptying the bladder
- Recent catheterization or urologic procedure
- Not being vaccinated against mumps
| Cause category | Examples | Typical clues |
|---|---|---|
| Viral orchitis | Mumps, other viral infections | Recent viral illness, fever, gland swelling, testicular swelling after systemic symptoms |
| Bacterial orchitis | UTI-related bacteria, spread from epididymitis | Urinary symptoms, fever, gradual pain, tenderness, possible scrotal redness |
| STI-related epididymo-orchitis | Chlamydia, gonorrhea | Sexual exposure risk, urethral discharge, burning with urination, unilateral pain |
Symptoms of orchitis
Symptoms can range from mild discomfort to severe pain. They often affect one side first, though both testicles may be involved in some cases.
Common signs and symptoms
- Testicular pain or aching
- Swelling of one or both testicles
- Tenderness to touch
- Scrotal redness or warmth
- Fever or chills
- Feeling run down or generally unwell
- Pain during urination or ejaculation in some cases
- Urethral discharge if an STI is involved
- Lower abdominal, groin, or pelvic discomfort
Symptoms may come on gradually with infection, but severe scrotal pain that begins suddenly should never be assumed to be orchitis without evaluation.
What’s normal vs what’s not?
It is normal for testicles to sit slightly unevenly or for one to hang lower than the other. It is not normal to develop a clearly swollen, painful, hot, or tender testicle—especially with fever or urinary symptoms.
| Finding | Often normal | Needs medical attention |
|---|---|---|
| Position | One testicle hangs lower than the other | Sudden change in position with acute pain |
| Mild brief discomfort | Occasional brief awareness after exercise or minor bump | Persistent or worsening pain lasting hours to days |
| Size | Minor natural asymmetry | Rapid swelling, visible enlargement, or new lump |
| Skin | Normal skin color and temperature | Redness, warmth, marked tenderness |
| General symptoms | No fever, no illness symptoms | Fever, chills, nausea, urinary burning, discharge |
Seek urgent care immediately if you have:
- Sudden severe testicular pain
- Nausea or vomiting with acute scrotal pain
- A high-riding testicle or unusual testicular position
- Rapid swelling after injury
- Severe pain with no clear cause
Those features raise concern for testicular torsion, which is a medical emergency.
Orchitis vs other causes of testicular pain
Not all scrotal pain is orchitis. Several conditions overlap in symptoms, and some require urgent treatment.
| Condition | What it is | Typical pattern | Why it matters |
|---|---|---|---|
| Orchitis | Inflammation of the testicle | Pain, swelling, tenderness, fever possible | May reflect infection and can affect fertility in some cases |
| Epididymitis | Inflammation of the epididymis | Usually gradual pain, swelling near back of testicle | Common, often infectious, may overlap with orchitis |
| Epididymo-orchitis | Inflammation of both epididymis and testicle | Combined tenderness, swelling, infection signs | Common real-world diagnosis |
| Testicular torsion | Twisting of the spermatic cord cutting blood flow | Sudden severe pain, nausea, abnormal testicle position | Surgical emergency |
| Hydrocele/varicocele | Fluid collection or enlarged veins | Heaviness or swelling, usually less acutely painful | May affect comfort or fertility but usually not an emergency |
| Testicular tumor | Abnormal growth in the testicle | Often painless lump, sometimes aching or heaviness | Needs prompt evaluation |
How orchitis is diagnosed
A clinician usually diagnoses orchitis through a combination of history, exam, and targeted testing. The goal is not only to confirm inflammation, but also to identify the cause and rule out emergencies.
What the evaluation may include
- Symptom review — when the pain started, whether it was sudden or gradual, whether there is fever, urinary burning, discharge, recent illness, sexual exposure, or trauma
- Physical exam — checking the testicles, scrotum, groin, and sometimes the abdomen and prostate
- Urinalysis and urine culture — to look for infection or blood
- STI testing — especially if chlamydia or gonorrhea is a possibility
- Scrotal ultrasound with Doppler — often used to assess blood flow, swelling, and rule out torsion or other structural issues
- Blood tests — sometimes used if systemic infection is suspected
Why ultrasound is often important
Scrotal ultrasound helps distinguish orchitis from conditions such as torsion, abscess, hydrocele, or tumor. Doppler imaging can show increased blood flow with inflammation or reduced blood flow with torsion.
What abnormal test results may mean
- Urine bacteria or white blood cells may support a urinary or bacterial source
- Positive STI testing can identify sexually transmitted causes
- Ultrasound findings may show enlarged, inflamed tissue or coexisting epididymitis
- Reduced blood flow is concerning for torsion rather than simple orchitis
Treatment for orchitis
Treatment depends on the underlying cause. Viral orchitis is usually managed supportively, while bacterial orchitis or epididymo-orchitis often requires antibiotics.
Common treatment options
- Antibiotics if bacterial infection or STI is suspected
- Pain relief with clinician-approved anti-inflammatory medication or other analgesics
- Rest to reduce strain and discomfort
- Scrotal support, such as supportive underwear
- Cold packs used carefully and briefly to help swelling
- Hydration and general recovery measures
- Treatment of sexual partners when an STI is diagnosed, depending on the infection
If the cause is viral
There is usually no specific antibiotic treatment for a purely viral case such as mumps orchitis. Care focuses on:
- Reducing pain and inflammation
- Supporting comfort during healing
- Monitoring for complications
If the cause is bacterial or STI-related
Prompt antibiotic treatment is important. The exact medication depends on the most likely organism, a person’s age, sexual history, urine findings, and local guidance. If an STI is suspected, it is important not to self-treat based on internet advice; proper testing and prescription treatment matter.
What not to do
- Do not ignore severe, sudden, or one-sided testicular pain
- Do not assume it is “just a strain” if swelling is obvious
- Do not rely on leftover antibiotics
- Do not return to sex before getting advice if an STI is possible
Can orchitis affect fertility?
Yes, it can—though the degree varies a lot. Some men have no lasting fertility effects. Others may have a temporary decline in semen quality, and a smaller subset may develop more significant testicular damage.
How orchitis may affect sperm and fertility
- Inflammation can disrupt sperm production inside the seminiferous tubules
- Fever and systemic illness can temporarily reduce sperm count and motility
- Severe inflammation may lead to testicular atrophy in some cases
- Bilateral orchitis poses a higher fertility risk than one-sided orchitis
Because sperm production takes time, semen changes may not be fully apparent right away. It typically takes around 2 to 3 months for a full sperm production cycle, so post-illness semen analysis is often interpreted with timing in mind.
When fertility testing may be worth discussing
- You had severe orchitis, especially in both testicles
- You are currently trying to conceive
- You notice testicular shrinkage after recovery
- You have low libido, symptoms of low testosterone, or other hormonal concerns
- You have had persistent pain or recurrent scrotal infections
Tests that may be relevant after orchitis
| Test | What it checks | Why it may matter after orchitis |
|---|---|---|
| Semen analysis | Sperm count, motility, morphology, volume | Assesses whether sperm production or quality may be affected |
| Hormone testing | Testosterone, FSH, LH, sometimes prolactin | Helps evaluate testicular and pituitary signaling |
| Repeat scrotal ultrasound | Structure, blood flow, residual changes | Useful if swelling persists or a mass is suspected |
| STI testing | Sexually transmitted infections | Important if infection source may not have been fully identified |
If fertility is a concern, it is reasonable to ask whether you should wait several weeks or months after recovery before checking a semen analysis, since acute illness itself can transiently alter results.
Recovery, healing time, and outlook
Recovery depends on the cause, severity, and how quickly treatment begins. Some men improve within days, while full resolution of tenderness or swelling can take longer.
What recovery often looks like
- Pain may improve before swelling fully settles
- Tenderness can linger even after infection is controlled
- Fatigue and body aches may improve once the infection or viral illness passes
- Follow-up may be advised if symptoms do not clearly improve
Possible complications
Complications are not inevitable, but they can include:
- Abscess formation
- Chronic scrotal pain
- Testicular atrophy
- Reduced fertility or impaired sperm production
- Rarely, reduced hormone production if damage is extensive
When symptoms should be rechecked
- You are not improving after starting treatment
- Pain or swelling is getting worse
- You develop a lump or persistent asymmetry
- You have recurrent episodes
- You are concerned about fertility or testicular size after recovery
Can orchitis be prevented?
Not every case can be prevented, but risk can be reduced.
- Stay up to date with recommended mumps vaccination
- Practice safer sex and get tested when appropriate
- Treat urinary symptoms promptly rather than waiting them out
- Follow up on recurrent UTIs or prostate symptoms
- Seek care early for new scrotal pain or swelling
Common misconceptions about orchitis
“If it’s orchitis, it can’t be an emergency.”
Not true. Acute testicular pain can be caused by orchitis, but it can also be caused by torsion, which needs immediate treatment.
“All testicular swelling is an STI.”
No. STIs are one possible cause, especially in epididymo-orchitis, but viral illness, urinary bacteria, and noninfectious conditions can also play a role.
“A painful testicle always means cancer.”
Most painful swelling is not cancer. Testicular cancer more often presents as a lump or painless enlargement, though any new testicular change should still be checked.
“If the pain improves, I don’t need follow-up.”
Sometimes improvement is enough, but persistent swelling, a residual lump, or fertility concerns deserve medical review.
“Orchitis always causes infertility.”
No. Many men recover without major long-term effects. Risk is higher in severe or bilateral cases.
Questions to ask your doctor
- Do you think this is orchitis, epididymitis, or something more urgent like torsion?
- What do you think is causing it—viral, bacterial, urinary, or STI-related?
- Do I need a scrotal ultrasound?
- Should I have urine testing or STI testing?
- If antibiotics are prescribed, what infection are they targeting?
- How long should pain and swelling take to improve?
- When is it safe to resume sex, exercise, or normal activity?
- Could this affect my fertility or testosterone?
- Should I get a semen analysis or hormone testing after recovery?
- What signs mean I should come back urgently?
Frequently asked questions
Is orchitis the same as epididymitis?
No. Orchitis is inflammation of the testicle, while epididymitis affects the epididymis. They often overlap, and when both are inflamed it is called epididymo-orchitis.
Can orchitis go away on its own?
Some viral cases improve with supportive care, but it is important not to assume. New or significant testicular pain should be evaluated because bacterial infection or torsion may need urgent treatment.
How long does orchitis last?
Symptoms may start improving within days once treatment begins, but swelling and tenderness can take longer to fully settle. Recovery time varies by cause and severity.
Can orchitis cause infertility?
It can, especially if it is severe or affects both testicles, but not every case leads to fertility problems. Some effects may also be temporary.
Does orchitis lower testosterone?
Most cases do not cause major long-term hormone failure, but severe testicular inflammation can affect testicular function. If symptoms of low testosterone appear after recovery, hormone testing may be appropriate.
How do doctors tell orchitis from testicular torsion?
They use the symptom pattern, physical exam, and often scrotal ultrasound with Doppler blood-flow imaging. Torsion usually causes sudden severe pain and is a true emergency.
Can an STI cause orchitis?
Yes. Chlamydia and gonorrhea can contribute, typically through epididymitis or epididymo-orchitis, especially in sexually active younger men.
Is orchitis contagious?
Orchitis itself is not something you “catch” from touching the scrotum. But the infection behind it may be contagious or transmissible, such as mumps or an STI.
Should I get a semen analysis after orchitis?
If you are trying to conceive, had severe or bilateral orchitis, or are worried about fertility, it is worth discussing with your clinician. Timing matters because semen quality can be temporarily affected after illness.
When should I worry about a painful swollen testicle?
Right away if pain is sudden, severe, associated with nausea or vomiting, or comes with marked swelling, fever, discharge, or a testicle that seems unusually positioned.
References
- Centers for Disease Control and Prevention (CDC). Sexually Transmitted Infections Treatment Guidelines.
- Urology Care Foundation. Patient information on epididymitis, orchitis, and related testicular conditions.
- Merck Manual Professional Edition. Epididymitis and Orchitis.
- NHS. Orchitis and epididymitis patient guidance.
- Mayo Clinic. Orchitis overview.
- American Urological Association (AUA). Urologic guidance and educational resources on acute scrotal conditions.
- World Health Organization (WHO). Mumps and vaccine-preventable disease information.
