Both psoriatic arthritis (PsA) and multiple sclerosis (MS) are inflammatory conditions that have environmental and genetic risk factors. However, there is limited scientific evidence that links exist between these two conditions.

Scientists have investigated whether having one of these conditions increases the risk of developing the other. While up to 25% of people with one autoimmune condition go on to develop another, evidence of a link between PsA and MS is inconclusive.

This article discusses what PsA and MS are, the possible links between these conditions, and treatments and lifestyle changes that can help reduce symptoms.

A healthcare professional examining the link between psoriatic arthritis and multiple sclerosis.Share on Pinterest
Mike Powell/Getty Images

The following table provides an overview of these two conditions.

PsAMS
Age of onset15–3520–40
Genderaffects males and females equallyaffects more women than men
Ethnicitymore common in people of European descentsimilar prevalence in African Americans and people of European descent
Symptoms• inflammation
• joint stiffness, swelling, and pain
• enthesitis
• visual disturbances
• fatigue
• pain
• loss of muscle strength
• psychiatric and cognitive changes
Affected areas• lower limbs
• fingers and toes
• spine
• eyes
• nails
• gastrointestinal tract
• ligaments and tendons
• brain
• spinal cord
Symptom severityvaries from person to personvaries from person to person

PsA

PsA is an autoimmune condition in which the body’s immune system targets the joints, causing inflammation, pain, and stiffness. It has an association with psoriasis — 20–30% of people with psoriasis also experience PsA.

Psoriasis affects more than 3% of U.S. adults. Scientists estimate that 15–30% of these people go on to develop PsA. Symptoms of PsA frequently develop 7–10 years after the first symptoms of psoriasis.

However, it is possible for a person to have PsA without psoriasis or to develop PsA before experiencing skin symptoms.

One of the key characteristics of PsA is enthesitis, which is a pain in the soles of the feet, the elbows, the back of the head, and other areas. Enthesitis is due to tenderness where ligaments and tendons connect to the bones.

MS

MS harms the central nervous system by destroying the myelin around nerve cells. According to the National Multiple Sclerosis Society, up to 913,925 people are living with MS in the United States.

MS affects vision, balance, motor ability, the bladder and bowels, and the senses. People who have MS may also experience mental health conditions such as depression and anxiety. Cognitive symptoms, such as difficulty remembering or concentrating, affect roughly half of all people with MS.

Researchers continue to study the similarities and differences between PsA and MS. There is some evidence that these conditions have a link; however, data is limited and sometimes conflicting.

The authors of a 2019 review suggest the following links:

Environmental risk factors

Both PsA and MS have known and unknown environmental risk factors. Viral infections and smoking are shared risk factors for these conditions.

However, scientists have identified environmental risk factors that these conditions do not share.

Fungal and bacterial infections, obesity, and increased stress levels are risk factors for PsA.

Risk factors for MS include UV radiation exposure, low vitamin D levels, and Epstein-Barr viral infections.

Genetic risk factors

Genetic analysis shows that these conditions share variations in Th-17 cells and IL-23 receptors.

However, each condition also has separate variations in these receptors.

Overactive immune system

Both PsA and MS are autoimmune conditions, which means the body’s immune system begins to target itself. People with either condition have an increase in IL-23 receptors and TNF-alpha cytokines, which cause inflammatory and autoimmune responses.

However, levels of IL-27 cytokines differ in people with these conditions. People with MS have lower levels of IL-27, whereas those with PsA have higher levels.

Both PsA and MS are multifactorial conditions, which means they have multiple causes, some of which scientists have not yet discovered.

PsA

Possible causes of PsA include:

  • bacterial infections such as strep throat
  • viral infections such as HIV
  • fungal infections
  • medications such as nonsteroidal anti-inflammatory drugs (NSAIDs)
  • smoking
  • obesity
  • stress

PsA may have a genetic factor. As many as 40% of people with the condition also have a family member who has it.

MS

Possible causes of MS include:

  • exposure to high levels of UV radiation
  • low vitamin D levels
  • Epstein-Barr viral infection
  • smoking

Recent research suggests that people who have had an Epstein-Barr viral infection are up to 32 times more likely to develop MS than those who have not contracted this virus.

Both PsA and MS require a comprehensive doctor’s examination for diagnosis.

PsA

Doctors may perform the following examinations and tests to diagnose PsA:

  • joint examinations
  • analysis of skin and nails
  • blood tests
  • skin biopsies
  • medical imaging, such as X-rays, MRIs, CT scans, and ultrasound

MS

A diagnosis of MS requires:

  • evidence of central nervous system damage in at least two places
  • evidence that damage took place at different times
  • ruling out other causes

Currently, the process for diagnosing MS can include:

  • a complete medical history
  • tests of cranial nerve function
  • tests of reflexes, sensation, balance, walking, and coordination
  • blood tests
  • MRI scans

Treatment for PsA and MS depends on the type and severity of symptoms a person is experiencing.

There is limited scientific research on treating people with both PsA and arthritis. However, a case study found that using two different monoclonal antibodies, natalizumab and secukinumab, was effective in reducing symptoms of both conditions. While this treatment is promising, the sample size of one person means more research is necessary.

PsA

Treatment for PsA can include:

The following strategies may be helpful for people with PsA:

  • regular gentle exercise, such as walking
  • use of shoe inserts and walking aids for support as necessary
  • regular stretching or yoga
  • aqua therapy
  • physical and occupational therapy

MS

Treatment for MS typically proceeds along three tracks:

  • managing symptoms of MS
  • finding ways to avoid flare-ups and lessen their impact when they occur
  • taking medication to slow the progression of damage due to MS

Doctors may prescribe monoclonal antibodies, beta interferon drugs such as Avonex and Refib, and immunosuppressants to reduce the severity of symptoms. People who experience muscle spasms or stiffness may benefit from muscle relaxants and tranquilizers such as baclofen.

Certain lifestyle habits may help a person with MS manage their symptoms. Suggestions include:

  • following a healthy, balanced, diet high in fruits, vegetables, and grains and low in processed foods
  • exercising regularly
  • avoiding extreme temperatures
  • maintaining regular sleep patterns

There is currently no way to prevent PsA or MS. However, people with these conditions can work closely with their healthcare team to identify and reduce the occurrence of flare-ups.

PsA

The following may help prevent PsA flare-ups:

  • monitoring symptoms
  • identifying and avoiding triggers
  • taking medications regularly
  • avoiding injury
  • exercising regularly to support joint suppleness
  • attempting to reduce stress, possibly with the help of practices such as meditation

MS

People with MS can work with their healthcare team to develop and follow a treatment plan to reduce the severity of symptoms. Treatment plans typically include:

  • disease-modifying therapies to slow MS progression
  • treatment to shorten relapses and reduce their severity
  • management of MS symptoms

Both PsA and MS are chronic conditions, which means they currently have no cure. People with these conditions experience symptoms that vary in severity.

PsA

Healthcare professionals classify PsA as an aggressive condition that can greatly impact a person’s quality of life. While some people may experience less pain and inflammation than others, experts associate the following factors with greater severity of the condition:

  • inflammation in a large number of joints
  • loss of function in the joints
  • damage to the joints

MS

MS symptoms are often mild in the beginning but become worse over time. People may begin to find it difficult to walk, although many people can still do so with support.

Additionally, MS may shorten a person’s life expectancy by 7–14 years in comparison to the general population.

PsA and MS are separate conditions with distinct qualities. They affect different parts of the body and have different symptoms.

However, they are both immune-mediated chronic conditions that cause inflammation. Researchers continue to explore the possibility that PsA and MS are linked. Currently, scientific evidence is inconclusive.