Psoriatic Arthritis in Children
Juvenile idiopathic arthritis (JIA; see entry Arthritis (Juvenile Idiopathic)) is the term for inflammation in a child’s joints, which will often be swollen, warm and painful, lasting for more than six weeks and with no identifiable cause. Psoriatic arthritis describes a small group of children with JIA whose arthritis may occur in conjunction with psoriasis, which is a red, silvery, scaling rash most commonly occurring on the elbows and knees.
The arthritis can start before the psoriasis in about half of cases. Both arthritis and psoriasis are common and they may also occur together by chance.
Medical text written November 2010 by Dr N Lessof, Locum Consultant Paediatrician and Dr C Pilkington, Consultant Paediatric Rheumatologist, Great Ormond Street Hospital, London, UK.
The symptoms of arthritis are warmth, swelling and pain in the affected joints. The affected joints are commonly the knees and ankles but also include the small joints of the hands and feet, and the wrists.
Uveitis is inflammation within the eye. It occurs in about 20 per cent of children with psoriatic arthritis. Children with uveitis often have no symptoms at all but may still have damage to their vision. It is very important for children with psoriatic arthritis to have regular eye checks to screen for uveitis.
Recognised patterns of psoriatic arthritis in adults include spondylitis (arthritis of the spine) and enthesitis (inflammation of the tendons), but children with these patterns of disease are classified as having different types of JIA.
Though the cause is unknown, it is recognised that approximately half of children with psoriatic arthritis have a first-degree relative with psoriasis.
The diagnosis of psoriatic arthritis is made clinically and with the family history. The diagnostic criteria have changed over the years. The current International League of Associations for Rheumatology (ILAR) criteria are:
- arthritis and psoriasis, or
- arthritis and two or more of:
- dactylitis (inflammation of fingers or toes)
- nail pitting (presence of small depressions on the nail surface) or abnormal nails
- family history of psoriasis in a first-degree relative.
Children are excluded from the diagnosis if they have positive blood tests for HLA B27 or for IgM rheumatoid factor. Blood tests may show signs of inflammation but this does not affect the diagnosis.
Non-steroidal anti-inflammatory drugs such as naproxen or ibuprofen are used to reduce pain and inflammation in affected joints. Methotrexate is a disease modifying anti-rheumatic drug, which will completely suppress disease activity in many children. If methotrexate does not work then new biological therapies are used to suppress disease activity.
Physiotherapy is important to recover muscle strength around affected joints. Occupational therapy is important if the hands or wrists are affected. Psychology support can be helpful in a variety of ways.
In a long-term follow-up study of children diagnosed using the old criteria for psoriatic arthritis, over half had grown out of their arthritis, and under half had persistent arthritis.
Though the condition is slightly more frequent in people with certain genetic markers, there is no clear inheritance pattern. It is very unusual to have more than one child in a family with arthritis.
Psoriasis and Psoriatic Arthritis Alliance (PAPAA)
The Alliance is a Registered Charity in England and Wales No. 1118192. It provides information and support to anyone affected by psoriasis or psoriatic arthritis, including specific information for parents of children with these conditions.
Group details last updated March 2016.