What is chronic inflammation of the joints associated with psoriasis, also known as psoriatic arthritis?
Psoriatic Arthritis is a disease affecting the whole body. It involves the chronic inflammation of several joints. Skin and/or nails are affected at the same time – and sometimes the eyes, as well. The skin involvement generally occurs before the joints are affected and may begin about ten years earlier. The joints most commonly affected are the knees; more rarely the terminal joints of the fingers, and, even more seldom, the ankles and the middle and terminal joints of the toes.
Psoriatic arthritis often begins gradually and is linked to painful swelling of the joints, redness and impaired movement. The spine is also often affected, more frequently in men than in women. A severe progression of the disease may result in destruction of the joints and vertebrae, particularly in the case of finger and toe joints.
In psoriatic arthritis, the patient often has only mild pain in the inflamed joints over a longer period of time. This means that major destruction of the joints may occur unnoticed.
The skin and nail changes in psoriatic arthritis and the available treatment options are described in the section about psoriasis vulgaris.
About 0.3 % - 1 % of the population suffers from psoriatic arthritis. The disease may occur at any age but is more common between the ages of 20 and 40.
What are the causes and risks for the development of psoriatic arthritis?
Psoriatic arthritis develops as the result of a malfunction in the immune system. The immune system has the task of detecting dangerous pathogens (germs), foreign substances and pollutants and eliminating them.
The body’s own tissue is normally recognised and tolerated by the cells of the immune system. However, if communication between cells is impaired, the immune system might start to attack the tissue of the body as well.
Psoriatic arthritis is not a hereditary disease. However, certain genes related to a predisposition to psoriatic arthritis are known.
What role does lifestyle play in the development of psoriatic arthritis?
Not all the potential factors have been precisely identified to date, but it is known that stress, physical or mental trauma and streptococcal infections may all trigger or exacerbate psoriasis or psoriatic arthritis.
It makes sense for every patient to find methods of avoiding or coping with stress situations.
Patients with psoriatic arthritis do not have to follow a special diet. Some patients report that certain substances will make an episode worse or even trigger a flare-up: alcohol and nicotine, for example. A mixed, balanced diet that is not too high in calories is recommended.
How is psoriatic arthritis diagnosed?
It is often difficult to diagnose psoriatic arthritis in the early stages of the disease. Most patients develop psoriasis first and are later diagnosed with psoriatic arthritis. In many cases only individual joints will be inflamed and the typical pattern of affected finger and toe joints is not present in all patients. Symptom-free periods occur between new flares of the disease, making the right diagnosis often difficult. A certain amount of time often passes before a reliable diagnosis of psoriatic arthritis can be made.
Examples for diagnostic procedures:
- Laboratory investigations of the blood
- X-ray examinations
- Ultrasound examinations
- Skin examinations
The doctor will decide on the best therapy for the individual patient on the basis of the diagnosis.
How is chronic joint inflammation in psoriatic arthritis treated?
Inflammations of the joints, bones and ligaments caused by the disease need to be reduced and pain alleviated.
It is important to slow down or stop disease progression to maintain the functional status of the joints.
The following therapeutic procedures are available
- Joint replacement
The doctor usually first prescribes fast-acting medicines, known as nonsteroidal anti-inflammatory drugs, at an appropriate dosage to treat any pain and inflammatory joint reactions. Anti-inflammatory medicines containing cortisone are also appropriate during acute episodes of the disease; these are usually taken in tablet form. If individual joints are severely inflamed, the doctor might also prescribe cortisone injections which he will inject directly into the joint capsule. The next stage of drug treatment includes long-term therapy with antirheumatic agents such as methotrexate, for example. If drug therapy does not lead to satisfactory improvement in the joints, surgery and joint replacement might be considered. Additional, targeted physiotherapy exercises can be considered to maintain mobility. Non-medicinal treatment measures, such as participation in self-help groups or taking part in patient training sessions, are also growing in importance.