The symptoms of ankylosing spondylitis (AS) can vary from person to person but usually develop slowly, over several months or years.
AS usually first starts to develop during later teenage years or early adulthood. The symptoms may come and go, and improve or get worse over many years.

Main symptoms

The main symptoms of AS are described below, although you may not develop all of these if you have the condition.

Back pain and stiffness

Back pain and stiffness are usually the main symptoms of AS. You may find:

• the pain gets better with exercise but doesn’t improve, or gets worse, with rest
• the pain and stiffness are worse in the morning and at night – you may wake up regularly during the night because of the pain
• you have pain in the area around your buttocks

Arthritis

As well as causing symptoms in your back and spine, AS can also cause inflammation of the joints (arthritis) in other parts of your body, such as your hips and knees. The main symptoms associated with arthritis are:

• pain on moving the affected joint
• tenderness when the affected joint is examined
• swelling and warmth in the affected area

Enthesitis

Enthesitis is painful inflammation where a bone is joined to a tendon (a tough cord of tissue that connects muscles to bones) or a ligament (a band of tissue that connects bones to bones).

Common sites for enthesitis are:

• at the top of the shin bone
• behind the heel (Achilles tendon)
• under the heel
• where the ribs join to the breastbone

If your ribs are affected, you may experience chest pain, and you may find it difficult to expand your chest when breathing deeply.

Fatigue

Fatigue is a common symptom of untreated AS. It can make you feel tired -and lacking in energy.