Sacroiliitis and ulcerative colitis

Ulcerative colitis affects the bowel, while sacroiliitis affects the sacroiliac joints at the back of the pelvis. Pain may be felt in the lower back, buttocks or hips, with stiffness that is worse after rest and eases with movement. Bowel symptoms such as diarrhoea or abdominal pain may be present, but joint symptoms can follow a separate pattern.

Back or buttock pain has many possible causes. Examination helps distinguish sacroiliitis from muscle strain, nerve pain and other joint conditions. Tell your clinician about morning stiffness, night pain, alternating buttock pain and any change in bowel symptoms.

Arrange a GP Consultation if new back or buttock pain lasts, limits movement or appears with bowel symptoms. Keep a simple record of pain, stiffness, activity, diarrhoea, bleeding and medicines. A clinician may coordinate care between gastroenterology, rheumatology and physiotherapy.

Do not stop ulcerative colitis treatment without advice. Ask before taking anti-inflammatory pain medicines because some can aggravate bowel symptoms in some people. Gentle movement and an individually planned exercise programme may help maintain mobility.

Seek prompt advice for persistent or worsening back pain, new weakness, painful red eyes, a swollen joint, fever, increasing diarrhoea or blood in the stool.

Get urgent help for loss of bladder or bowel control, numbness around the groin, severe weakness in both legs, inability to walk, fainting or severe abdominal pain with a swollen abdomen.

Ask whether your symptoms suggest sacroiliitis, whether imaging or blood tests are needed, which pain relief is safest with ulcerative colitis, and how your bowel and joint treatments can be coordinated.