Psoriatic Arthritis

Psoriatic arthritis is inflammatory arthritis occurring in people who have psoriasis. The same immune process that thickens and scales the skin also inflames the lining of the joints, the points where tendons anchor into bone, and in some people the spine and the joints at the base of it.

The skin usually comes first, often by several years, but the joints can be affected before any rash appears or while the skin is so mild it has never been diagnosed. The severity of the skin does not predict the severity of the joints, so extensive psoriasis can come with untroubled joints and a single patch on the scalp can accompany aggressive arthritis. Changes in the nails, pitting, ridging and separation of the nail from its bed, are one of the more reliable markers that the joints may become involved.

It affects men and women about equally and usually starts between thirty and fifty. Several distinct patterns exist: a few large joints, many small joints symmetrically, the joints nearest the fingertips, the spine, and swelling of an entire finger or toe. Fatigue is a genuine part of the disease and is not proportional to how the joints look.

Your rheumatologist examines every joint systematically, counting which ones are tender and which are swollen, and records the counts so that the response to treatment can be measured against them later. They pay particular attention to whether a whole digit is swollen along its length, since that is close to specific for this condition.

They press at the enthesis points, at the heel, the sole, the elbow and around the pelvis, where tenderness indicates inflammation at tendon insertions, and they assess spinal movement and chest expansion.

The skin examination is deliberate and includes the places psoriasis hides: the scalp under the hair, behind and inside the ears, the navel, the natal cleft and the nails. A patch found in one of those changes the diagnosis, so expect to be asked to uncover them.

Blood tests play a supporting role only. Inflammatory markers are normal in a substantial proportion of people who have active disease, and the antibody associated with rheumatoid arthritis is usually negative here, which helps separate the two. X-rays of the hands and feet establish a baseline, and ultrasound or MRI is used where the examination is equivocal.

Treatment is assessed in months and the first two years carry the most weight, since joint damage accumulates fastest early and is permanent once it has occurred. That is the argument for starting treatment promptly instead of waiting to see how it goes.

Anti-inflammatory tablets and a steroid injection into a particular joint give relief within days to a couple of weeks and are used while slower treatment takes hold. Disease-modifying tablets need about three months of regular use before their effect can be judged, and they require blood tests every few weeks at the start to monitor the liver and the blood count.

Where those are insufficient, targeted biological treatments are considered, and they are usually assessed at twelve to sixteen weeks. Screening for tuberculosis and hepatitis is done before starting them, which matters particularly in India, and monitoring continues throughout. Once you are stable, expect reviews every three to six months with the joint counts repeated each time. Keeping moving and keeping weight down both improve the response to whatever medication you are on.