Pediatric Psoriatic Arthritis

Psoriatic arthritis is a rare form of arthritis or joint inflammation that affects both skin and joints. Psoriasis is an ongoing (chronic) condition that causes a red, scaly, itchy rash. It also causes nails to become thick and pitted with tiny holes.

Psoriatic arthritis causes joint pain and painful swelling, along with skin rashes. It most often affects finger and toe joints. But it can also affect wrists, knees, ankles, and the lower back.

This condition is most common in adults ages 30 to 50, but it can start in childhood. In many cases, the skin disease starts before the arthritis. In children, psoriatic arthritis is a form of juvenile idiopathic arthritis.

Early diagnosis and treatment help to ease pain and prevent joint damage from getting worse.

The cause of psoriatic arthritis isn’t known. But a child’s immune system, genes, and the environment may play a role. Children with this condition often have a family member with arthritis or psoriasis.

The skin condition psoriasis may start before or after the arthritis. Psoriasis causes a scaly, red, itchy rash on the knees, elbows, scalp, face, and the folds of the buttocks. It can also cause pitting of fingernails or toenails.

Each child’s symptoms may vary. Symptoms of psoriatic arthritis may include:

• Inflamed, swollen, and painful joints, usually in the fingers and toes
• Morning stiffness in the joints
• Reddened skin over the affected joints
• Sausage-like swelling of fingers and toes, plus swollen wrists (more common in girls ages 1 to 6)
• Deformed joints from chronic inflammation
• Symptoms in the spine or sacroiliac joint (more common in older children)
• Eye pain
• Lack of energy (fatigue)
• The symptoms of psoriatic arthritis can seem like other health conditions. Make sure to see your child’s healthcare provider for a diagnosis

Psoriatic arthritis is easier to confirm if your child already has psoriasis. If the skin symptoms have not yet occurred, diagnosis may be more difficult. Your child’s healthcare provider will take your child’s health history and do a physical exam. They will ask about your child's symptoms. Your child may have blood tests, such as:

• Erythrocyte sedimentation rate (ESR or sed rate). This test looks at how quickly red blood cells fall to the bottom of a test tube. When swelling and inflammation are present, the blood's proteins clump together and become heavier than normal. They fall and settle faster at the bottom of the test tube. The faster the blood cells fall, the more severe the inflammation.
• Uric acid. High blood uric acid levels are linked to psoriatic arthritis.
• Complete blood count (CBC). This test checks for low counts of red blood cells (anemia), white blood cells, and platelets.
• Antibody blood tests. These tests are done to look for certain kinds of proteins, called antibodies, in your blood. These tests can be positive for many kinds of rheumatic diseases. Younger children are more likely to have a positive antinuclear antibody (ANA) test.

Other tests may include:

• X-rays. This test uses a small amount of radiation to create images of organs, bones, and other tissues.
• Eye exam. This is done by a pediatric eye doctor (ophthalmologist).The exam looks for uveitis, a swelling of the middle layer of the eye.

Treatment will depend on your child’s symptoms, age, and general health. It will also depend on how severe the condition is.

The treatment team will include your child's primary healthcare provider. It will also include a pediatric rheumatologist and an ophthalmologist.

Treatment is done for both the skin condition and the joint inflammation. Some medicines used to treat psoriatic arthritis include:

• Nonsteroidal anti-inflammatory drugs (NSAIDs) to relieve symptoms. These include aspirin, ibuprofen, and naproxen.
• Medicines that weaken the body’s immune system (immunosuppressives). These can be used to ease inflammation if NSAIDs are not working.
• Vitamins and minerals to slow bone deformities. These include calcium and vitamin D.
• Biologic medicines such as infliximab
• Corticosteroids to ease redness and swelling

Other treatment may include:

• Ultraviolet light treatment (UVB or PUVA)
• Heat and cold
• Splints
• Exercise
• Physical therapy to improve and keep muscle and joint function
• Occupational therapy to improve ability to do activities of daily living
• Managing the psoriasis skin rash
• Surgery to fix or replace a damaged joint (often not needed until years after diagnosis)

Children with psoriatic arthritis are at risk of having an eye condition called uveitis. This is an inflammation of the eye’s middle layer.

With early diagnosis and treatment, children can go into remission. This means that symptoms go away. But when treatment is delayed, remission is less likely. Then the condition may lead to long-term disability.

Help your child manage their symptoms by sticking to the treatment plan. This includes getting enough sleep. Encourage exercise and physical therapy, and find ways to make it fun. Work with your child's school to make sure your child has help as needed. Work with other caregivers to help your child take part as much possible in school, social, and physical activities. Your child may also qualify for special help under Section 504 of the Rehabilitation Act of 1973. You can also help your child find a support group to be around other children with pediatric arthritis.