What is enthesitis-related arthritis (ERA)?
Arthritis means "joint swelling" or "joint inflammation." It is a disease that leads to pain, swelling, stiffness and loss of motion in the joints. There are many different types of arthritis. Enthesitis-related arthritis (ERA) is one type. Enthesitis is swelling or inflammation of the entheses, the connective tissue where tendons or ligaments attach to bone. Juvenile ERA is managed by rheumatologists, doctors who specialize in diseases of the joints and inflammation.
To learn more, please read "Juvenile enthesitis-related arthritis (ERA)."
ERA is treated with medicine
Your child may need to take different kinds of medicine for ERA:
- Some types of medicine can improve symptoms of inflammation. These medicines are called non-steroidal anti-inflammatory drugs (NSAIDs). They help to reduce pain and stiffness and improve movement in the joints. Examples of NSAIDs are naproxen, indomethacin, and ibuprofen.
- Some people with ERA need stronger medicines that suppress the immune system and help control inflammation to prevent joint damage. These stronger medicines include prednisone, methotrexate, sulfasalazine, and biologics.
- Sometimes, the doctor may suggest joint injections as a way to quickly decrease the inflammation.
The medicine is prescribed based on your child's body size. The aim is to use as little medicine as possible to take away the inflammation and symptoms of ERA.
It is hard to predict how long your child will need to take medicine. Some children will only need to take medicine for a short time. Other children will need medicine for a longer time.
Most drugs have some side effects. These effects are not part of the treatment. If your child is given a drug, the doctors or nurses will let you know about the drug's possible side effects.
There may be other treatments available as well. Researchers are always learning more about ERA and how to treat it.
Non-steroidal anti-inflammatory drugs (NSAIDs)
Non-steroidal anti-inflammatory drugs (NSAIDs) include naproxen, ibuprofen, indomethacin, and meloxicam. NSAIDs help to improve the symptoms of ERA, including pain and stiffness, and help improve joint movement. It can take up to four to eight weeks to see the full effects of these medicines.
NSAIDs are available as liquids, pills or capsules. Depending on the specific medicine given to your child, they will need to take them once, twice or three times a day.
The doses of these medicines are based on your child's body size. While your child is on an NSAID they should not take any other NSAIDs, such as ibuprofen (Advil or Motrin).
The biggest complaint or side effect from this family of medicines is an upset stomach or stomach pain. Please let your doctor know if your child is experiencing any side effects.
Medicines that suppress the immune system
Your child may be prescribed medicine that suppresses the immune system. It lowers the number of immune cells that are attacking your child's joints and entheses.
Prednisone
Prednisone may be chosen when multiple joints and entheses are inflamed.
Sometimes children with ERA need to use prednisone for a short period to control inflammation and to allow time for other medicines to start to work. Your child will be prescribed a dose based on their body size, and the dose will be lowered over time (weaned).
It is very important that your child take the exact amount of prednisone that the doctor prescribes. Prednisone dosage must be lowered slowly. Stopping prednisone suddenly can lead to serious harm to your child's body.
Sulfasalazine
Sulfasalazine is another medicine that can be used for ERA. It is "second-line" and can be used when NSAIDs alone do not decrease the inflammation. It can take up to three months to see the full effects of this medicine.
Sulfasalazine comes in pill or liquid form. Your child will take it by mouth twice a day. It is taken with a snack or meal to prevent stomach upset.
Children with an allergy to sulfa medicines cannot take sulfasalazine. Please let your doctor know if your child has a history of this allergy.
Your child will need regular blood tests to monitor for side effects. Sulfasalazine can sometimes stop the body from making white blood cells, red blood cells, or platelets.
Methotrexate
Methotrexate is also a second-line medicine. It is used when NSAIDs alone do not decrease inflammation. It can take up to three months to see the full effects of this medicine.
Methotrexate is taken by mouth (pill or liquid) or by injection once a week. If your child takes methotrexate by pill form, it must be taken on an empty stomach.
If your child is prescribed methotrexate, they will also need to take a vitamin called folic acid in order to help reduce side effects.
Some children develop nausea or mouth ulcers while taking this medicine. If your child has nausea or upset stomach, try giving the dose before bed; this may help them sleep through the side effects. Both nausea and mouth ulcers can be avoided by taking folic acid.
Your child will need regular blood tests. These tests are done for two reasons:
- To make sure the methotrexate does not stop your child's body from making white blood cells, red blood cells, or platelets
- To make sure the methotrexate is not affecting the liver, which helps to break down the medicine
Biologics
Biologics are a newer group of medicines used to treat ERA. They are used when NSAIDs or other medicines have not properly controlled the inflammation. In children with ERA, the immune system sends chemicals called cytokines throughout the body. These chemicals go to the joints and entheses and cause inflammation. Biologics are able to block some of these cytokines from being made and can greatly reduce or stop inflammation.
Some biologics are etanercept (Enbrel), infliximab (Remicade), and adalimumab (Humira). These medicines are either given by an injection under the skin or by an intravenous (IV) infusion into a vein.
Biologics usually do not have very many side effects. The most serious side effect is a greater risk for infections, because biologics are stronger at suppressing the immune system. Your child will need tests for certain infections, such as tuberculosis, before starting on a biologic.
Joint injections
Sometimes for children with ERA, the doctor may suggest joint injections as a way to quickly decrease inflammation. Usually, your child will feel less pain and swelling and better movement within one to two days (24 to 48 hours) after the injections. Joint injections are done when only one or a few joints are a problem.
Joint injections are done with a small needle. The doctor injects a long-acting steroid directly into the joint space.
To ensure that your child is comfortable during this procedure, the injections may be done with local anaesthetic, sedation, or general anaesthetic. Your rheumatologist will discuss with you what will be best for your child.