Your son's scrotum is the sac that holds the two testicles. Scrotal swelling is a common problem seen in young boys and baby boys. It can have many causes. These are usually divided into painless and painful scrotal swelling.

Causes of painless scrotal swelling

Painless swelling can come on suddenly or slowly over time.

Here are some of the more common causes:

  • Hernias and hydroceles. These are the most common causes of scrotal swelling. They are caused by abnormal openings left behind when the testicles descend into the scrotum during development.

    Hydroceles are collections of fluid that pass down into the scrotum and are present in about 10 percent of baby boys at birth. If an opening does not close by itself, a portion of intestine may pass through the opening. This is called a hernia. Hernias occur in about 1 percent of boys.

  • Varicoceles. These painless swellings are cause by enlarged veins in the scrotum that drain the testicles and send blood back to the heart. They are present in 10 to 15 percent of young boys and are more common on the left side of the scrotum.

  • Other causes. Less common causes include idiopathic scrotal edema and tumors of the testicle. Idiopathic is a term used when doctors don't know what is causing a condition. In this case, there can be rapid scrotal swelling in young boys, but it goes away on its own. Testicular tumors are extremely rare in boys younger than age 15 and account for less than 2 percent of all cancers in children.

Causes of painful scrotal swelling

Painful scrotal swelling can start suddenly or gradually. Painful swelling is less common than painless swelling, but is usually more serious, especially if it is severe and sudden.

Here are some common causes:

  • Testicular torsion. This condition is caused when a testicle twists on its cord. A twisted cord can cut off a testicle's blood supply and may require emergency surgery— ideally within six hours of the onset of symptoms to prevent death of the testicle. Pain is sudden and severe. Testicular torsion occurs in about one out of 4,000 boys. It is most common in infants and boys between ages 12 and 18. Boys often experience pain from a blow to the groin while playing or during sports—any pain from injury to the testicles that lasts longer than an hour is considered abnormal and a reason for immediate medical attention.

  • Epididymitis and orchitis. These are infections that can be caused by bacteria or viruses. Pain is less severe and more gradual than with torsion. Viral infection of the testicle (orchitis) can be seen in young boys who contract mumps. Epididymitis, marked by a feeling of heaviness, tenderness, and swelling in the scrotum, is usually a bacterial infection of the ducts near the testicle that are important for the storage and development of sperm. Several sexually transmitted diseases, including chlamydia and gonorrhea, can cause epididymitis. When it occurs in older boys, it may be because of unprotected sexual activity. In young boys, it is usually because of an abnormality somewhere in the urinary tract.

  • Zipper entrapment. If part of the scrotum, foreskin, or penis gets caught in a zipper, it can cause immediate, agonizing pain. Emergency room doctors commonly treat both pain and injury while freeing the entrapped tissue.

  • Other causes. Less common causes of painful swelling include other injuries, allergic reactions, and insect bites. Schönlein-Henoch purpura is a condition that may cause painful scrotal swelling in young boys along with rash, joint pain, stomach pain, and blood in the urine; its cause is unknown.

Diagnosis and treatment of scrotal swelling

Any scrotal swelling needs to be examined by your child's doctor. The diagnosis begins with taking a medical history and asking about when the swelling started and how painful it is. A physical examination will include an examination of the belly, the scrotum, and the testicles.

In almost all cases, the doctor will request a urine sample to look for signs of infection. The medical team may also do an ultrasound exam, which involves taking pictures of the structures inside the scrotum by using sound waves.

Depending on the findings, treatment may require:

  • Surgery. For testicular torsion, emergency surgery is usually needed to save the testicle. Surgery may also be needed in cases of a hernia that traps some intestine in the scrotum or a severe injury to the testicle.

  • Antibiotics. If the doctor finds evidence of bacterial infection, he or she will prescribe antibiotics. Young boys who are not sexually active should also have special X-ray studies to look for an abnormality in their urinary system as a possible cause of infection.

  • Observation and other treatments. For conditions like minor trauma, mumps, small hernias, hydroceles, idiopathic swelling, and Schönlein-Henoch purpura, no treatment may be needed. Many of these conditions can be watched to see whether they clear up on their own. Other conditions need attention. Without treatment, varicoceles may over time result in infertility and testicular injury that is not reversible. Testicular cancer in boys responds very well to cancer drugs. Pain medicines and medicines that reduce swelling may also be used during observation for some of these conditions.

If your child has scrotal swelling at any age, he should be seen by his doctor. Most scrotal swelling is not painful, but still needs to be evaluated. Painful scrotal swelling, especially swelling that is severe and starts suddenly, is a medical emergency and needs to be evaluated right away.

For more information or to schedule an appointment, call 314.454.5437 or 800.678.5437 or email us.