Illustrative Case. Clearance of Psoriasis with infliximab but persistent joint pain due to underlying degenerative arthritis

Background of Patient

65 year old lady with 20 year history of psoriasis.

Patient was taking methotrexate for psoriasis.

Patient developed severe extensive psoriasis with a PASI score of >10.

The patient also had mild generalised joint pains but did not see a Rheumatologist.

Following prescription of Infliximab 5mg/Kg every 6 weeks the skin cleared completely.

However, the patient had persistent joint pain which was disappointing as she understood that this would resolve under therapy.

The patient had low back pain and the query was whether the patient had an enthesitis related arthritis.

A Rheumatology consultation was organised.

Patient History and findings in Rheumatology

The patient complained of pain in the right sacroiliac joint region and low back.

The patient also had neck pain.

The pains were worse as the day went on.

The pains were worse with prolonged standing and prolonged walking.

There was an absence of early morning stiffness.

There was no history of joint swelling.

Examination findings and investigations

Tenderness over the posterior sacroiliac joint on the right side was noted.

Some cervical spine tenderness was noted.

The C-reactive protein was normal.

A diagnosis is psoriasis and degenerative arthritis was made.

Further x-rays were not arranged based on the clear clinical diagnosis.

Tramadol 100mgs three times per day was prescribed with good effect.


The pain was not of an inflammatory back pain character.

The superficial tenderness in the lower back is usually considered to represent sacroiliitis but is often due to sprain or strain of the posterior sacroiliac ligaments.

The actual inflammatory pain associated with sacroiliitis may be emanating from deep within the bones and is therefore not associated with tenderness of superficial structures on medical examination.

There is no evidence that dose adjustment of anti-TNF will help this pattern of joint pain.

Inappropriate therapy dosage increases could add to the costs of an already expensive therapy and could put the patient at an increased risk of complications.

It is important to recognise that pain in psoriatic patients under anti-TNF therapy could be related to degenerative arthritis.

Clear explanation of the difference between inflammatory and mechanical enthesopathy is necessary.

Basically the difference is between predominant inflammation and predominant wear and tear.

Analgesia may help.