Black spots on your scrotum are usually caused by a condition called angiokeratoma of Fordyce. These spots are made up of blood vessels that have expanded, or dilated, and become visible on the surface of your skin.

They may feel bumpy and rough to the touch, and they’re normally dark purple or red rather than deep black. Angiokeratoma of Fordyce can also appear on the shaft of your penis and around your inner thighs.

These spots usually aren’t cause for concern, especially if you don’t have any other symptoms. Keep reading to learn why these spots appear, other symptoms you should watch out for, and what to expect from treatment.

In many cases, the exact cause of angiokeratoma of Fordyce is unknown. Some research suggests that high blood pressure (hypertension) in the veins of your scrotum may play a role in their appearance.

They may also be more likely to appear if you’ve ever experienced:

Fabry disease (FD) is one of the only known causes of angiokeratoma of Fordyce. This condition is extremely rare, happening in only about 1 out of every 40,000 to 60,000 men.

FD results from a mutation in your GLA gene. This gene is responsible for producing an enzyme that helps cells break down fat. With FD, your cells can’t break down a certain type of fat that then accumulates throughout your body. Having too much of this fat in your body can hurt the cells in your heart, kidneys, and nervous system.

There are two types of FD:

  • Type 1 (classic). Fat builds up in your body quickly from birth. Symptoms start appearing when you’re a kid or a teenager.
  • Type 2 (later-onset). Fat builds up more slowly than in type 1. You may not see any signs of the condition until you’re in your 30s or even as late as your 70s.

These spots usually show up in clusters. You may have as many as 100 spots on your scrotum at a given time. Although they may become irritated or bleed if you scratch them, they likely won’t cause you any pain otherwise.

Most people don’t experience any other symptoms alongside the black spots. If your spots are the result of FD, other symptoms may not appear until you’re older.

In addition to black spots on your scrotum, FD can cause:

  • sharp pain in your hands and feet, especially after strenuous activity or exercise
  • not sweating enough (hypohidrosis)
  • ringing sounds in your ears (tinnitus)
  • visible eye cloudiness
  • bowel symptoms, such as diarrhea and constipation

You should see your doctor as soon as you can if you notice black spots on your scrotum. They’re usually harmless, but your doctor will help diagnose or rule out any conditions like FD.

Your doctor will perform a physical examination and ask you about your medical history. Because FD is passed down genetically, you may also be asked about your family’s medical history.

Other tests your doctor may perform include the following:

  • Imaging tests, such as CT scans or X-rays, are used to look at parts of your body that might be affected by an underlying condition. This includes your heart or kidneys.
  • Lab tests are used to check for the mutation that causes FD. Your doctor may do this with a blood, urine, or skin tissue sample.
  • Tissue samples (biopsies) are used to test for the enzyme that breaks down fat in cells. A biopsy can also test the spots for cancerous cells to determine if they’re melanomas, which result from a rare form of skin cancer.

On their own, angiokeratoma of Fordyce don’t need treatment. But if the spots are causing irritation or otherwise bothering you, talk to your doctor about removal.

They may recommend one of the following removal techniques:

  • Electrodesiccation and curettage (ED&C). Your doctor uses a local anesthetic to numb the area around the spots. Once the area is numb, they use tools to scrape the spots off and remove the tissue.
  • Laser removal. Your doctor uses laser techniques, such as a pulsed dye laser, to remove the expanded blood vessels that are causing the black spots.
  • Cryotherapy. Your doctor freezes the tissue around the black spots and remove them.

Treatment for FD

FD can be treated with a medication called agalsidase beta (Fabrazyme). This medication needs to be injected regularly to help your body break down the extra fat that has built up in your cells. The GLA gene mutation prevents your body from creating enough of a certain enzyme to break the fat down naturally.

Your doctor may also prescribe medication to treat pain in your hands and feet. This includes gabapentin (Neurontin) or carbamazepine (Tegretol).

In most cases, black spots on your scrotum are harmless. Still, you should see your doctor for diagnosis. They can determine whether these spots result from FD.

FD may require long-term treatment to manage fat buildup in your cells and its associated symptoms. If left untreated, FD may lead to heart failure, kidney failure, or stroke.

FD can also lead to symptoms of depression. Joining an FD support group or foundation, however, may help you feel more connected to others with this rare condition and empower you to maintain a high quality of life: