Diffuse idiopathic skeletal hyperostosis (DISH) is calcification or a bony hardening of ligaments in areas where they attach to your spine.

Also known as Forestier disease, diffuse idiopathic skeletal hyperostosis causes stiffness in your upper back, and may also affect your neck and lower back. Some people experience diffuse idiopathic skeletal hyperostosis beyond the spine in areas such as their heels, ankles, knees, hips, shoulders, elbows and hands.

Diffuse idiopathic skeletal hyperostosis often causes no symptoms, though stiffness and pain along affected ligaments can occur. You may not need treatment for diffuse idiopathic skeletal hyperostosis if you don't have symptoms, though physical therapy may help you maintain range of motion in your affected joints.

The signs and symptoms you experience depend on which part of your body is affected by diffuse idiopathic skeletal hyperostosis. The upper portion of your back (thoracic spine) is most commonly affected. Signs and symptoms may include:

• Stiffness. Stiffness may be most noticeable in the morning.
• Pain. You may feel pain when someone presses on the affected area. Not everyone with diffuse idiopathic skeletal hyperostosis experiences pain.
• Loss of range of motion. Loss of lateral range of motion may be most noticeable. You flex your spine laterally when you do side stretches, for example.
• Difficulty swallowing or a hoarse voice. You may experience these symptoms if you have diffuse idiopathic skeletal hyperostosis in your neck (cervical spine).

It isn't clear what causes diffuse idiopathic skeletal hyperostosis, but doctors have some idea of what can increase your risk of the condition. Risk factors include:

• Certain medications. Long-term use of medications called retinoids, such as isotretinoin (Accutane, others), that are similar to vitamin A can increase your risk of diffuse idiopathic skeletal hyperostosis. It isn't clear whether high intake of vitamin A increases your risk, however.
• Sex. Men are much more likely than women are to develop diffuse idiopathic skeletal hyperostosis.
• Older age. Diffuse idiopathic skeletal hyperostosis is most common in older adults, especially in people older than 50.
• Diabetes and other conditions. People with diabetes may be more likely to develop diffuse idiopathic skeletal hyperostosis than are those who don't have diabetes. Other conditions that may raise insulin levels in your body may also increase your risk, including hyperinsulinemia, prediabetes and obesity.

Make an appointment with your doctor if you have persistent pain or stiffness in any joint or in your back.

To determine whether you have diffuse idiopathic skeletal hyperostosis, your doctor may begin with a physical examination. He or she will press lightly on your spine and joints to feel for abnormalities. Any pain you experience from the pressure on your spine may be a clue to the diagnosis. Diffuse idiopathic skeletal hyperostosis may cause pain at the point where the affected tendon or ligament attaches to a bone. Your doctor may be able to detect bone spurs.

In order to confirm diffuse idiopathic skeletal hyperostosis, your doctor will order X-rays, which may show calcification along the bones that make up your spine (vertebrae). The calcification has a distinct appearance that doctors sometimes refer to as cascading or flowing. Some compare the appearance to that of candle wax dripping and oozing down your spine.

Other types of imaging, such as computerized tomography (CT) and magnetic resonance imaging (MRI), may be helpful in diagnosing diffuse idiopathic skeletal hyperostosis. These tests can also rule out conditions that may cause similar signs and symptoms, such as ankylosing spondylitis.

People with diffuse idiopathic skeletal hyperostosis are at risk of certain complications, such as:

• Disability. Loss of range of motion in the affected joint can make it difficult to use that joint. For instance, diffuse idiopathic skeletal hyperostosis in your shoulder can make it difficult and painful to use your arm.
• Difficulty swallowing. Bone spurs associated with diffuse idiopathic skeletal hyperostosis in the neck (cervical spine) can put pressure on your esophagus, making it difficult to swallow. The pressure from bone spurs can also cause a hoarse voice or difficulty breathing while you're asleep (sleep apnea). In rare circumstances this can become serious and may require surgery to remove the bone spurs.
• Paralysis. Diffuse idiopathic skeletal hyperostosis that affects the ligament running up the outside of your spine (posterior longitudinal ligament) can put pressure on your spinal cord. Spinal cord compression may result in a loss of feeling and paralysis.

While there's no cure for diffuse idiopathic skeletal hyperostosis, there are steps you can take to reduce pain and stiffness if you're experiencing those symptoms. In many cases, treatment may not be necessary. However, if you experience symptoms of diffuse idiopathic skeletal hyperostosis, your doctor may recommend treatments to control pain and maintain range of motion in your affected joints.

Treatment for pain
Treatment for pain caused by diffuse idiopathic skeletal hyperostosis is similar to that of other joint ailments. Your doctor may recommend pain relievers, such as acetaminophen (Tylenol, others) or nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil, Motrin, others). More severe pain can be treated with corticosteroid injections.

Treatment for stiffness
Physical therapy can reduce the stiffness associated with diffuse idiopathic skeletal hyperostosis. Exercises may also increase your range of motion in your joints. Ask your doctor about specific exercises you can do. He or she may refer you to a physical therapist for further guidance.

Surgery
Surgery may be required in rare cases when diffuse idiopathic skeletal hyperostosis causes severe complications. People who experience difficulty swallowing due to large bone spurs in the neck may need surgery to remove the bone spurs. Surgery may also relieve pressure on the spinal cord caused by diffuse idiopathic skeletal hyperostosis.

To help you manage any pain and stiffness you experience with diffuse idiopathic skeletal hyperostosis, try these self-care measures:

• Exercise regularly. Regular aerobic exercise, such as walking or swimming, can increase your endurance, keep your body more nimble and help you cope with diffuse idiopathic skeletal hyperostosis. Talk with your doctor before you start an exercise program.
• Apply heat. Use a heating pad on areas of your body that are affected by diffuse idiopathic skeletal hyperostosis to reduce pain. Set the heating pad at a low setting so that it's warm, not hot, to reduce the risk of burns.