Herniated disk

Doctors do not know why some cases of sciatica become chronic.

Many acute and chronic cases happen because of a herniated disk. In most cases, herniated disks improve on their own within a few weeks. When they do not, this may cause chronic pain.

Injury

People with herniated disks often remember a specific injury that triggered the pain.

An injury does not mean that the pain will be chronic.

However, people who have a herniated disk from an injury may develop the same injury again, especially if they continue repeating the movements that led to it.

Inflammation

Inflammatory conditions can trap spinal nerves, causing sciatic pain.

People with chronic inflammatory conditions, such as rheumatoid arthritis, may notice that their sciatica flares when their condition gets worse.

Treating the underlying condition may help treat the sciatica.

Infection

An infection in or around the spine can cause an abscess, which is a swollen and infected mass. This abscess can trap spinal nerves, causing sciatica and, sometimes, other symptoms.

A person with an abscess may develop a fever, have pain in other areas of the body, or find that sciatica begins after they have another infection.

Spinal mass or cancer

Any type of mass in or near the spine may trap spinal nerves, causing sciatic pain.

Some masses are cancerous. In other cases, an epidural hematoma, which is a swollen blood spot near the spine, can cause the pain.

It is important that people with sciatica see a doctor to rule out potentially dangerous conditions such as cancer, especially when sciatica does not go away.

Wear and tear

As a person ages, the normal wear and tear on their spine can cause the spinal column to narrow, resulting in spinal stenosis.

For some people, spinal stenosis causes chronic or worsening pain.

Lifestyle issues

Several lifestyle factors may increase the risk of sciatic pain or extend the healing time.

People with these risk factors may find that sciatica becomes chronic or recurs. Risk factors for sciatica include:

• little physical activity and prolonged sitting
• having overweight or obesity
• smoking

As sciatica often follows an injury, people may also find that the symptoms do not improve if they continue the activity that caused the original injury.

Spinal misalignment

When the spine is not properly aligned, such as when a person has scoliosis or another chronic condition, it can put pressure on the space between the vertebrae.

This pressure may cause herniated disks. It can also compress the sciatic nerve, causing nerve pain. Depending on the cause, a person may need surgery, physical therapy, or other treatments.

Sciatica can and does come back, especially when a person has a chronic medical condition.

People who do not make lifestyle changes to prevent more sciatic pain may also redevelop symptoms. However, for most people, sciatica heals on its own within a month or two.