If you’ve just been diagnosed with rheumatoid arthritis (RA), your primary concern is going to be your joints. But RA is a systemic disease, meaning the inflammation that’s affecting your joints can also target other parts of the body. So, for that matter, can the drugs used to treat RA.

While some of the side effects listed here might be alarming, they’re far more likely to happen to people who’ve had moderate-to-severe RA for a long time and whose disease hasn’t been well-controlled with medication than those who are newly diagnosed or whose disease has been mild or under control. That being said, it’s important to become educated about the effects of this disease – and the drugs used to treat it – as early as possible so you can manage it better later on.

No matter what stage of RA you’re in, if you experience any of the signs or symptoms mentioned here, it’s imperative that you tell your doctor as soon as possible. She’ll determine the cause – or causes – and adjust your treatment plan accordingly.

Skin

About half of the people with RA develop rheumatoid nodules – lumps of tissue that form under the skin, often over bony areas exposed to pressure, such as fingers or elbows. Unless the nodule is located in a sensitive spot, such as where you hold a pen, treatment may not be necessary. Nodules sometimes disappear on their own; disease-modifying antirheumatic drugs (DMARDs), a category of drugs that inhibits the disease process, can cause them to vanish as well.

Skin is also susceptible to RA drugs. Corticosteroids, which mimic the naturally occurring hormone cortisol to control inflammation, can cause thinning of the skin and susceptibility to bruising. Non-steroidal anti-inflammatory drugs (NSAIDs), which treat inflammation, and Methotrexate, a widely prescribed DMARD, can cause sun sensitivity. People taking biologic response modifiers, or biologics, a sub-category of DMARDs designed to stop inflammation at the cellular level, may develop a rash at the injection site.

Eyes

Some people with rheumatoid arthritis may develop an inflammation of the eyes known as scleritis. Symptoms include pain, redness, blurred vision and light sensitivity. Treatment is usually eye drops, NSAIDs or a corticosteroid. A rare complication of scleritis is scleromalacia perforans, in which the eye may be permanently damaged by severe inflammation. RA can also cause uveitis, an inflammation of the area between the retina and the white of the eye, which, if not treated, could cause blindness. As a rule, people with RA should get eye checkups at least once a year. Corticosteroids may cause glaucoma and cataracts; hydroxychloroquine, in rare cases, causes pigment changes in the retina.

Mouth

No one knows why, but people with RA tend to have a higher rate of gum disease, or gingivitis. Excellent oral hygiene is a must. Medications such as methotrexate can cause mouth sores or oral ulcers. For treatment, try a topical pain reliever or ask your doctor or dentist for a prescription mouthwash.

Lungs

About a third of people with RA will develop some type of lung or pulmonary symptom. Pleurisy, an inflammation of the lung lining, can make it painful to take a deep breath but is treatable with anti-inflammatory drugs. Some people with RA develop scarring called pulmonary fibrosis, which leads to progressive shortness of breath. Rheumatoid nodules might form in the lungs, but are usually harmless.

RA drugs may affect the lungs as well. Methotrexate can cause a complication known as methotrexate lung or methotrexate pneumonia, which generally goes away when the methotrexate is stopped. Less common drugs, including injectable gold and penicillamine, can cause similar pneumonias. The condition goes away when treatment ceases; patients can usually resume the drug in a few weeks.

The risk of contracting tuberculosis (TB – a bacterial infection of the lungs), is elevated in people with RA and intensifies among those taking corticosteroids, DMARDs and biologics. Your doctor should test for TB before initiating treatment and periodically after.

Heart

Research shows that people with RA are about 2.5 percent more likely to develop cardiovascular disease than the general population. Researchers suspect it’s because the inflammation that characterizes RA spreads to blood vessels. RA can also cause pericarditis, inflammation of the heart lining, which may manifest as chest pain. In general, people with RA should address lifestyle factors associated with heart disease such as eating a healthy diet, exercising and not smoking.

Liver

Though there’s no direct link between RA and the liver, medications can affect this vital organ. Studies show that long-term use of the analgesic acetaminophen (Tylenol) is considered a leading cause of liver failure. Liver diseases may also occur with long-term methotrexate use. Working with your rheumatologist to monitor your blood is key to preventing problems.

Kidneys

Kidney problems are more likely related to side effects of RA drugs – such as cyclosporine or an NSAID – than to the disease itself. If you're taking one of these drugs or methotrexate, which concentrates in the kidneys, your doctor will monitor your kidney function to watch for problems.

Blood

Letting the inflammation that accompanies RA go unchecked can cause anemia – a reduction in red blood cells characterized by headache and fatigue. Inflammation might also lead to thrombosis, or elevated blood platelet levels, and blood clots. Both conditions improve as the inflammation is controlled; anemia can be further addressed with iron supplements. On the other hand, aggressively treating inflammation with corticosteroids may cause thrombocytopenia, an abnormally low number of blood platelets. This, too, is addressed by stopping the medication.

Though it’s rare, people with longstanding RA can develop Felty syndrome, characterized by an enlarged spleen and low white blood cell count. This condition may lead to increased risk of infection and lymphoma, cancer of the lymph glands. Immunosuppressant drugs are the usual treatment.

Blood Vessels

It’s rare, but longstanding RA can also cause vasculitis, inflammation of small blood vessels that supply the skin. Such involvement may have serious consequences if not addressed, although aggressive treatment with methotrexate, corticosteroids and other drugs that control cell production usually resolves the problem. Vasculitis is often heralded by small red dots on the skin; more severe cases can cause ulcers on the legs, under fingernails or in nail beds.

Nervous System

Nerve problems in the arms or legs, such as numbness, tingling or weakness, sometimes occur with RA. People with RA may develop carpal tunnel syndrome, a common nerve condition in which the nerve that runs from the forearm to the hand is compressed by inflamed tissue, resulting in tingling, numbness and decreased grip strength.

Sjögren’s Syndrome

People with rheumatoid arthritis are at greater risk for Sjögren’s syndrome, a condition in which the immune system attacks the body’s moisture-producing glands. The result: eyes and mouth that feel dry and gritty. Dry eyes can be relieved with “artificial tear” eye drops. In severe cases, a surgical procedure to plug the tear ducts may help. 

If left untreated, the condition can result in eye infection and scarring of the conjunctiva – the membrane covering the white of the eye inside the eyelid. Prescription medications can stimulate saliva production; so can sucking on sugarless lemon drops or glycerin swabs. Good dental hygiene is a must, as bacteria tend to flourish in a dry mouth, leading to tooth decay and gum disease.