The short answer: yes. Fever is actually one of those early subtle symptoms of rheumatoid arthritis (RA) that you might overlook or chalk up to something else.
In up to one-third of people with rheumatoid arthritis, the telltale RA joint pain occurs with “systemic” (or all-over) symptoms that include fatigue, muscle pain, mood changes, and low-grade fever, according to UpToDate. Some patients describe these non-joint symptoms of RA as being “flu-like” — that general yucky feeling you get when you’re on the verge of getting sick.
Normal body temperature ranges from 97°F to 99°F. A low-grade fever is generally considered less than 101°F.
Why Does Rheumatoid Arthritis Cause Fever?
The reason low-grade fever is common among RA patients has to do with how your body’s immune system works. When your immune system is revved up — say, to fight a cold or flu virus that’s entered your body — it produces a number of proteins that take different actions to attack the germs and get you healthy again. Fever can occur as a result of this immune system activation.
With an inflammatory autoimmune disease like rheumatoid arthritis, your immune system is switched on, but is attacking your body’s own tissues rather than a foreign invader like a virus or bacteria. This autoimmune response is what can cause a low-grade fever in rheumatoid arthritis.
Once you get diagnosed with RA and start treatment — which typically includes a disease-modifying drug or biologic to act on the immune system and stop unnecessary inflammation — systemic RA symptoms such fever and fatigue should improve too. However, you may develop low-grade fever every now and then as your RA disease activity ebbs and flows.
“Fever is not a disease [all by itself]; it is a manifestation of some inflammatory process that could be rheumatoid arthritis, infections, or something else,” says Alexa Meara, MD, a rheumatologist at The Ohio State University Wexner Medical Center in Columbus, Ohio.
Rheumatoid Arthritis Fever and Infection Risk
While your overactive immune system may cause fever, it’s also important to remember the other reason fevers occur: because you’re fighting an infection, such as a virus (cold or flu) or bacteria (strep throat).
Certain medications you take to manage your arthritis suppress your immune system, which makes you more vulnerable to infection than the general population, says Yvonne Lee, MD, an associate professor of rheumatology at Northwestern University Feinberg School of Medicine and a Northwestern Medicine rheumatologist.
So if you develop a fever and have already been diagnosed with rheumatoid arthritis, it could be because you’re sick — and not just part of your usual disease activity.
When to Tell Your Doctor About Having a Fever
If you have a fever of more than 100.4°F, tell your doctor, Dr. Meara advises. They can help figure out if you’re fighting an infection and determine whether you need additional medical care.
“It’s really important to get evaluated to see if you need antibiotics or further treatment because we don’t want any potential infection to get out of hand,” Dr. Lee says. “Get it evaluated by either your primary care physician or your rheumatologist. Don’t assume it’s your RA and carry on.”
Depending on the situation, your doctor may advise you to stop certain RA medications while you’re sick with an infection. However, never stop taking any medication you take to treat RA without first consulting your doctor.
While temporarily stopping certain immune-modifying medications can allow your body to heal itself by re-engaging your immune system’s natural fighting abilities, this isn’t always necessary or a good idea, depending on your dosing schedule and other factors. Stopping medication may let the body heal itself, but may also worsen your RA symptoms.
“Sometimes it does become a catch-22, and really depends on the situation, the patient, and their disease,” Dr. Meara says.
How to Treat Fevers When You Have Rheumatoid Arthritis
Most of the time, you can treat RA fevers the same way you would treat any other fever:
- Take an over-the-counter medication such as acetaminophen or ibuprofen (check with your doctor to make sure they are safe to take with any other medications you’re on)
- Drink plenty of fluids
- Dress in layers so you can stay warm if you get chills and disrobe if you get hot
- Place a cold compress on your forehead or neck
- Nap, rest, and get a good night’s sleep
Fever as a Symptom of Rheumatoid Arthritis Flares
Fever may be a sign of an RA flare coming on, but Dr. Meara says it’s very dependent on your individual disease. “We definitely want to know if a patient feels feverish, especially if it’s something different than how they normally feel,” she says. Dr. Lee adds that it isn’t common for her to see fever as a sign of flare for her patients.
Bottom line: It’s important to know your baseline for everyday symptoms — including pain, stiffness, swelling, fatigue, and fever — once you’ve been diagnosed with inflammatory arthritis. This helps you understand when your aches and pains are normal, and when something is off.