When you have arthritis, buttoning a shirt or fastening a clasp can be a pain in the butt. So is folding laundry with achy joints, blow drying your hair or even signing paperwork. But then there is genuine pain that can occur in your buttocks — and it may be caused by arthritis.

The buttock is a large area, with many different structures within it, explains Claudette Lajam, MD, an orthopedic surgeon with NYU Langone medical centre in New York City. The giant muscle at the surface of the buttocks is called the gluteus maximus. It overlies other layers of muscle and two major joints: the hip joint and sacroiliac (SI) joints, which are situated on each side of your spine and connect the sacrum (base of your spine) to the ilium (top part of your pelvis).

Buttock pain may indicate a problem in either of the sacroiliac joints, the lumbar spine (lower back), the muscles of the pelvis or any of those other layers, says Dr Lajam, who also serves as spokesperson for the American Academy of Orthopaedic Surgeons.

How Arthritis Can Cause Buttock Pain

“Any form of arthritis that affects the hips or lower back can cause buttock pain,” says Dr Lajam. Some types include:

Osteoarthritis of the hip

The hip is a ball-and-socket joint. The “ball” is the top of your thigh bone, and it sits in a “socket” that is formed by part of your pelvic bone. Slippery tissue called cartilage covers the bone surface and helps cushion the joint. Osteoarthritis (OA) occurs when the protective cartilage gradually wears down, which over time leads to pain and stiffness. The most common symptom of hip osteoarthritis is pain around the hip joint. As hip OA disease progresses, low-grade inflammation can set in, explains physical therapist Colleen Louw, PT, spokesperson for the American Physical Therapy Association (APTA). That results in increased sensitivity of the surrounding nerves, which can cause pain in and around the low back and buttocks.

Osteoarthritis of the spine

The bones in your spine (vertebra) are separated by spongy discs, which act as shock absorbers. With age, these discs can wear or shrink, which narrows the space between the spinal joints, or “facet” joints. “The facet joints are a series of small joints in the lower back that contain the same type of cartilage that is found in your knees,” explains Louw. Disc changes can lead to more strain on the joints, which can cause the cartilage to wear down and the facet joints in the vertebrae to rub against one another, leading to the pain and stiffness of OA. “It is not uncommon for these joints to refer pain into the buttocks, especially with prolonged standing or even walking,” says Louw.

Ankylosing spondylitis (AS)

Ankylosing spondylitis is a form of arthritis that causes inflammation in the joints in your spine — especially your lower spine — and/or your SI joints. Over time, inflammation can cause some of the vertebrae to fuse, which makes your spine less flexible and leads to chronic pain and discomfort. Early symptoms of AS are frequent pain and stiffness in the lower back and buttocks, which comes on gradually over the course of a few weeks or months. Some people even use the phrase “alternating buttock pain” to describe their AS symptoms.

Rheumatoid arthritis (RA)

With rheumatoid arthritis and other forms of inflammatory arthritis, the immune system mistakenly attacks a protective lining in your joint called the synovium and destroys cartilage. Though RA tends to affect smaller joints first (such as those in your hands and feet), symptoms can spread to both your hips as the disease progresses. Inflammatory arthritis in your hip will feel painful and stiff. You may also experience a dull or aching pain in the buttocks that’s worse in the morning and gradually improves with activity.

Other Reasons for Buttock Pain

“Unless there is a direct trauma that occurs to the buttock itself, such as from a direct injury, buttock pain is usually referred from somewhere else,” says Louw. Here are other reasons aside from arthritis that your butt may be in pain.

Muscle strain

Your buttocks are made up of three muscles: the gluteus maximus, the gluteus medius and the gluteus minimus. You can strain one of these or other overlapping muscles in the area, which can cause pain, says Dr Lajam. “The hamstrings attach right at the bottom of the pubic bone,” she says; “injury or tears of the hamstrings can cause deep buttock pain. Sprains or strains of the abductor muscles (the side muscles of the hip) can cause buttock pain.”

Injury/bruising

Your buttocks may develop a painful bruise (or black-and-blue mark) if you get hurt; for example, from falling on an object or getting kicked. You may notice swelling, discolouration and tenderness to the touch.

Bursitis

This painful condition occurs when the small, fluid-filled sacs — called the bursae — that cushion the bones, tendons and muscles near your joints become inflamed. The most common causes are repetitive motions or positions that put pressure on the bursae around a joint. Bursitis most often affects the shoulder, elbow and hip. “Bursitis of the hip can lead to buttock pain,” says Dr Lajam.

You also have bursae in your buttocks called ischial bursa, which can become inflamed and cause ischial or ischiogluteal bursitis. This can result from sitting for a long time on a hard surface, direct trauma or injury to the hamstring muscle or tendon from activities like running or bicycling.

Sacroiliitis

This is an inflammation of the SI joints, which can cause pain in your buttocks, and well as your lower back, hips or groin. Some forms of inflammatory arthritis, such as ankylosing spondylitis and psoriatic arthritis, as well as osteoarthritis, can cause sacroiliitis, so might an injury, pregnancy or infection.

Sciatica

Pain that radiates from your lower back to your buttock and down the back of your leg is the hallmark symptom of sciatica. It most commonly occurs when a herniated disk, bone spur on the spine or narrowing of the spine (spinal stenosis) compresses part of the sciatic nerve. Injuries or overuse of the piriformis muscle, which is located in the buttocks near the top of the hip joint, can contribute to sciatica too. This causes inflammation, pain and often some numbness in the affected leg. The pain can range from a mild ache to a sharp, burning or excruciating pain. Usually, only one side of your body is affected.

How to Ease Buttock Pain from Arthritis

If you’re experiencing buttock pain and you’re not sure why, it’s a good idea to make an appointment with your GP. They may refer you to a rheumatologist or orthopedic doctor depending on your symptoms and circumstances.

If you’re already diagnosed with arthritis and are experiencing buttock pain that’s new or different, it’s important to let your doctor know. You might have an additional kind of arthritis or injury alongside your current diagnosis. (For example, buttock pain could be a sign that you have osteoarthritis in your spine in addition to rheumatoid arthritis.)

Step one for buttock pain treatment is following your arthritis treatment plan, says Dr Lajam. Taking your medication as prescribed and maintaining a healthy weight can help relieve buttock pain caused by arthritis. Your doctor may recommend steroid injections in affected joints to help relieve the related buttock pain.

Staying active is highly recommended for managing your buttock pain. Exercises that help stretch and strengthen low back, hip and buttock muscles can also ease your pain. Your doctor may advise physical therapy which can be customised for your needs.

Keep Reading

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This article has been adapted, with permission, from a corresponding article by Teresa Dumain on the CreakyJoints US website. Some text and information have been changed to suit our Australian audience.