Doctors do not believe that hand, foot, and mouth disease (HFMD) causes rheumatoid arthritis (RA). However, a small number of case reports suggest it may trigger reactive arthritis, a type of joint swelling and inflammation.

It is a myth that HFMD causes RA. In rare cases, it may cause reactive arthritis, which is similar to RA. However, reactive arthritis is a distinctly different condition.

Doctors do not fully understand what causes RA, but researchers think genetic and environmental factors likely play a role. It is possible that some viruses could trigger a reaction in the immune system that leads to RA. However, no recent research has looked at HFMD.

People with RA, an autoimmune condition, are at risk for infections. Additionally, treatments for RA suppress immune function.

Read on to learn more about HFMD and RA.

An X-ray of the pelvis.Share on Pinterest
Reza Estakhrian/Getty Images

There is no strong scientific evidence that HFMD causes RA. Some research, however, suggests that people may develop joint pain after HFMD infection.

The coxsackievirus causes HFMD, which is particularly common among children, especially those under the age of 5. It is unusual for it to affect adults who do not have underlying conditions that weaken the immune system.

Rarely, a person may develop joint pain or swelling following an HFMD infection.

This happens when the immune system overreacts to an infection, attacking the joint tissues. Doctors previously called this Reiter syndrome but now usually refer to it as reactive arthritis. A 2016 case report details the experiences of a 3-year-old male who developed reactive arthritis in his left knee following an HFMD infection. Other case studies have shown the same thing, but there are no large-scale studies looking at HFMD and reactive arthritis.

Additionally, there is no research linking RA and HFMD.

Scientists think that infections sometimes trigger RA in people who are genetically susceptible to the condition. For example, some studies suggest that the Epstein-Barr virus may contribute to the development of RA. People who are genetically predisposed to RA may respond differently to the Epstein-Barr virus than those who are not.

Much like the Epstein-Barr virus, it is possible that the coxsackievirus may also trigger RA. However, scientists have not conducted well-designed studies to test this possibility.

A person may also develop RA following an HFMD infection by mere coincidence. Having RA after HFMD does not necessarily mean that the virus caused it.

The symptoms of HFMD, RA, and reactive arthritis include the following.

Symptoms of HFMD

People with HFMD may experience:

  • fever and feeling sick
  • flu-like symptoms
  • sores on or around the mouth
  • a rash on the feet or hands that may spread to other areas, such as the genitals or elbows
  • increased crying in babies and young children

There is no specific treatment for HFMD, and it usually gets better on its own in a week or two. However, it is important to manage symptoms, prevent dehydration by drinking plenty of water, and stay home from work or school.

Symptoms of RA

People who develop joint pain after HFMD may worry that they have RA. It is not possible to distinguish RA from other types of arthritis, such as reactive arthritis, based on symptoms alone.

Some symptoms of RA include:

Symptoms of reactive arthritis

RA typically causes pain in multiple joints, while reactive arthritis may cause pain in just one joint.

Symptoms of reactive arthritis include:

Doctors often diagnose HFMD based on symptoms. A doctor can also diagnose the infection by taking a swab of the blisters or looking for signs of the virus in the blood. However, this testing is not usually necessary since there is no specific treatment for HFMD.

If a doctor thinks a person may have RA, they will also diagnose based on symptoms, medical history, and lab tests. No single test can conclusively diagnose RA. Some tests they might perform include:

Learn more about how doctors diagnose RA.

The long-term effects of RA and HFMD vary.

RA and reactive arthritis effects

RA is a progressive, chronic condition. This means it is a long-term disease that may gradually worsen over time.

As RA progresses, it may attack other healthy tissue in the eyes, nerves, and organs. This can cause infections, chronic pain, vision problems, and other health issues such as cardiovascular disease and lung involvement. It also increases a person’s risk of certain cancers.

Unlike RA, reactive arthritis usually goes away within 3–12 months.

HFMD effects

Most people with HFMD recover on their own. However, sometimes HFMD can affect the central nervous system, heart, or other important organs. This increases the risk of serious complications, especially in babies and young children.

A 2021 study tracked outcomes in people hospitalized with HFMD. Over the follow-up period of a median of 4.3 years, neurodevelopmental and similar complications were common in the group with severe HFMD, with 25% developing neurological abnormalities.

People who had cardiorespiratory failure also had higher rates of long-term complications. According to the study, 57% of these people showed brain abnormalities on an MRI, and 71% had motor skill difficulties.

A person should contact a doctor if:

  • they have symptoms of HFMD
  • symptoms of HFMD do not clear within 2 weeks
  • they become very ill with HFMD
  • they develop joint pain with HFMD
  • they have RA and develop HFMD

Hand, foot, and mouth disease (HFMD) usually resolves on its own without any serious side effects. In rare cases, people may develop rheumatoid arthritis (RA) after HFMD. However, this does not mean HFMD caused RA. People may also get reactive arthritis after HFMD.

Researchers do not fully understand the cause of RA. It is possible that some viruses may play a role in its development, and certain infections can trigger the condition in people predisposed to RA.

People who think they may have arthritis or HFMD should contact a doctor.