What is reactive arthritis?

Reactive arthritis^[1], previously known as Fiessinger-Leroy disease, is a form of inflammatory arthritis that develops as a result of an infection—most commonly, one in the genitals, urinary tract, or gastrointestinal (GI) tract.Reactive arthritis also used to be referred to as Reiter’s syndrome. However, it is now identified as a type of arthritis called spondyloarthritis^[2]. Spondyloarthritis, which refers to a group of inflammatory diseases, is divided into two subgroups: peripheral arthritis (which affects the joints in the arms, legs, fingers, and feet) and axial arthritis (which affects the spine). Reactive arthritis most commonly affects the knees and the joints in the ankles and feet. However, the inflammation characteristic of the disease can also develop in the eyes, skin, or urinary tract. The symptoms of reactive arthritis, which include joint pain, swelling, and inflammation, usually develop within a few days to weeks after a GI infection or genitourinary infection (which affects the genitals and urinary tract).

What is arthritis?

Arthritis^[3] is a condition that causes inflammation (swelling) in the joints (the points in the body at which bones meet, such as the knees, wrists, fingers, toes, and hips). Arthritis is a progressive condition, meaning it gets worse as time goes on. There are over 100 different types of arthritis. Some forms of the disease, such as osteoarthritis, may be caused by normal wear and tear associated with aging. Others, including rheumatoid arthritis and reactive arthritis, result from autoimmune issues. The underlying cause of and treatment options for a patient’s arthritis will depend upon which form of the disease they have.

How common is reactive arthritis?

The incidence of reactive arthritis is very low: between 0.6 and 27 people out of every 100,000^[4] are reported to have the disease. Men in their twenties and thirties are the most likely to develop reactive arthritis. Generally, between 2–4% of people develop reactive arthritis after a genitourinary infection (usually from a Chlamydia trachomatis). Up to 15% of people with gastrointestinal infections may develop reactive arthritis, while 1–3% of people with inflammation of the urethra will have at least one arthritis episode.

Reactive arthritis causes

Reactive arthritis is triggered by sexually transmitted or foodborne bacterial infections. While the condition itself is not contagious, the infections that lead to reactive arthritis can often be passed from person to person. A number of bacteria can cause^[5] reactive arthritis, including:

• Chlamydia trachomatis: Associated with a sexually transmitted infection commonly known as chlamydia, which causes genitourinary symptoms.
• Salmonella enteritidis: Associated with a foodborne infection commonly known as salmonella, which causes gastrointestinal symptoms.
• Neisseria gonorrhoeae: Associated with a sexually transmitted infection commonly known as gonorrhea, which causes genitourinary symptoms.
• Mycoplasma genitalium: Associated with a sexually transmitted infection that causes genitourinary symptoms.
• Ureaplasma urealyticum: Associated with a sexually transmitted infection that causes genitourinary symptoms.
• Shigella flexneri: Associated with a foodborne infection commonly known as shigella, which causes gastrointestinal symptoms.
• Yersinia enterocolitica: Associated with a foodborne infection commonly known as yersinia, which causes gastrointestinal symptoms.
• Campylobacter jejuni: Associated with a foodborne infection commonly known as campylobacter, which causes gastrointestinal symptoms.
• Clostridioides difficile: Associated with a foodborne infection commonly known as C. diff, which causes gastrointestinal symptoms.

Risk factors for reactive arthritis

Some factors^[6] may increase your risk of developing reactive arthritis, including:

• Age: Reactive arthritis is typically diagnosed in people between the ages of 20 and 40.
• Sex: Males are more likely to develop reactive arthritis from sexually transmitted infections than women. Conversely, both men and women are equally likely to develop reactive arthritis as a result of foodborne infections.
• Inherited genes: Some people with reactive arthritis carry the gene HLA-B27^[7]. While it is possible to develop reactive arthritis without carrying this gene, those with the gene frequently have symptoms that are more severe and quicker to onset. People with HLA-B27 are also more likely to develop long-lasting, or chronic, symptoms of reactive arthritis.
• Prior infection: Having had a sexually transmitted infection or illness from foodborne bacteria in the past can increase your risk of developing reactive arthritis.

Reactive arthritis symptoms

Reactive arthritis can affect multiple body systems. Because of this, it can cause symptoms that are widespread or occur in different parts of the body. The symptoms most frequently seen with reactive arthritis are joint inflammation, urinary tract inflammation, and eye infection (conjunctivitis). Typically, people who develop reactive arthritis begin showing symptoms within one to four days to a few weeks of their initial infection. Symptoms may last for three months to as long as one year. In roughly 25%^[8] of people, the condition may develop into a chronic (long-lasting) disease. The signs and symptoms of reactive arthritis overlap with those common to arthritis as a whole. Common signs and symptoms of arthritis (which has over 100 forms) include:

• Joint pain and stiffness in the knees, feet, or ankles
• Inflammation of the tendon where it attaches to the bone (called enthesitis)
• Swelling of the toes or fingers
• Heel spurs (painful, bony growths on the heel)
• Inflammation of the spine or lower back joints

Urinary tract infection (UTI) is one of the most common causes of reactive arthritis. UTIs are bacterial infections that can occur anywhere along the urinary tract, though they commonly affect the lower urinary tract (urethra or bladder). The symptoms of UTIs can differ between males and females. Women are more likely to develop UTIs because the length of the female urethra is shorter than that of a male. Approximately 40–60% of women will develop a UTI during their lifetime. Common signs and symptoms of UTIs in women include:

• Frequent urges to urinate/frequent urination
• Inflammation of the vulva/vagina
• Inflammation of the fallopian tubes
• Inflammation of the cervix or cervical area
• Inflammation of the urethra, leading to burning during urination

In men, UTIs may present with:

• Burning during urination
• Discharge^[9] from the penis
• Inflammation of the prostate
• Increased urine production and frequent urination
• Frequent urges to urinate, even after urinating recently

Reactive arthritis may also be caused by conjunctivitis (eye infection). Common signs and symptoms of conjunctivitis include:

• Red, irritated whites of the eyes
• Blurry vision
• Inflammation of the inner eye
• Inflammation of the tissue membrane covering the eyeball (sclera)

The signs and symptoms of reactive arthritis, as well as their severity and duration, will vary based on a number of factors, including what underlying infection is causing the condition. Talk to your healthcare provider if you experience any of the signs or symptoms of arthritis after having an infection.

Reactive arthritis rash

As high as 10%^[10] of people with reactive arthritis may develop a rash^[11] known as keratoderma blennorrhagica. This rash presents as skin lesions on the palms of the hands, soles of the feet, front of the legs, tips of the fingers, toes, or nails. These lesions can be open sores, scaly patches, or hard, tender lumps. Keratoderma blennorrhagica, a rare complication of reactive arthritis, has been associated with^[12] Chlamydia trachomatis infections. This skin rash, as well as another rash called psoriasiform dermatitis¹⁰, is frequently seen in individuals with reactive arthritis who are HIV-positive. These lesions can be reddish, raised, and waxy. With treatment, these lesions usually resolve^[13] within four weeks.

Complications from reactive arthritis

In most cases, the symptoms of reactive arthritis resolve^[14] within weeks to months. Some people, however, may continue to have symptoms for as long as a year. Even more rarely, some people go on to develop chronic and severe arthritis. When it becomes chronic,^[15] reactive arthritis can affect quality of life (the ability to live a full and active life). Quality of life can refer not only to health factors, such as mobility, but also to environmental and economic factors, such as the ability to work, go to school, or socialize. The arthritis-specific¹⁰ scale of measuring quality of life examines physical, social, and emotional well-being through factors such as dexterity, pain, mobility, physical and social activity, depression, and anxiety. Extensive studies^[16] have shown that people with chronic arthritis report significantly greater impairments in quality of life than those without arthritis. Specifically, people with arthritis report significantly more days during which their usual activities are affected by their condition and their physical and mental health are worse than usual.