What to Know About the Link Between Multiple Sclerosis and Psoriatic Arthritis

Overview of MS

MS is an autoimmune disease where your immune system mistakenly attacks healthy tissue called myelin. This is the substance that forms the protective sheath covering your nerve fibers.

Damage to the myelin coat around your nerves interrupts nerve impulses between your brain, spinal cord, and the rest of your body. This causes MS symptoms such as:

• bowel and bladder problems
• cognitive changes
• difficulty walking
• dizziness
• fatigue
• emotional changes
• muscle weakness
• numbness and tingling
• spasticity
• vision problems

The nerves themselves may also develop irreversible damage.

Statistics suggest that almost 1 million people in the United States live with MS. Globally, that number is estimated to be about 2.8 million people.

Overview of PsA

PsA is a chronic, inflammatory type of arthritis that can accompany the skin condition psoriasis (PsO).

Psoriatic conditions are autoimmune diseases that occur when your immune system mistakenly attacks your healthy tissues. In the case of PsA, that tissue is your joints. For PsO, it’s the skin.

Usually, PsO skin symptoms occur first before PsA manifests in your joints. However, it’s also possible for arthritic symptoms to occur before a skin rash. On rare occasions, people with PsA never develop skin symptoms.

About 1 in 4 people with PsO develop PsA, so many people with psoriasis never experience joint issues.

If you live with severe PsO, you have a higher chance of developing PsA.

Similarities and differences

PsA and MS have characteristics in common.

They both:

• are autoimmune conditions
• are not contagious
• have genetic and environmental risk factors
• are chronic (long lasting) and inflammatory
• have no cure
• have a range of symptom severity that varies from person to person
• can be progressive and worsen over time
• have symptoms that come and go (flares and remissions)

There are also several differences:

Potential links between PsA and MS

While more research is needed on the links between MS and PsA, a 2019 review of research found that psoriasis is significantly associated with an increased chance of developing MS.

There are a few key links that may explain this connection:

Overactive immune system

With autoimmune conditions, the immune system reacts to things it should not — namely, your body’s healthy tissue.

Both PsA and MS share this type of immune-mediated origin.

For example, the cytokines TNF-alpha and IL-23 play a role in the inflammatory response for both PsA and MS. Cytokines are proteins that control the growth and activity of immune cells and blood cells.

Genetic risk factors

You don’t inherit PsA or MS directly. But you can inherit genes that may make you more likely to develop either condition.

An estimated 33–50% of people living with PsA have a first-degree relative with PsA or PsO.

MS also has a strong family link. In identical twin studies, when one twin has MS, the chance their identical twin will also develop MS is 1 in 4. In the general population, the chance of a person having MS is about 1 in 334.

Researchers have identified about 200 genes that are related to someone’s chance of developing MS.

Environmental risk factors

Environmental or modifiable risk factors that PsA and MS share include:

• Overweight: Excess body weight produces cytokines, which increase inflammation.
• Tobacco use: Tobacco increases inflammation, according to a 2020 study that found higher levels of TNF-alpha in the blood of cigarette smokers than control participants.
• Vitamin D deficiency: Vitamin D suppresses inflammation by boosting the action of one type of immune cell (T helper 2) and suppressing another (T helper 1).
• Stress: Research links stress to an activation of the inflammatory response.
• Infection: Some infections can cause the immune system to attack your own healthy cells through actions like molecular mimicry.

PsO is strongly associated with bacterial, fungal, and viral infections, such as:

• HIV
• streptococcus
• staphylococcus aureus
• helicobacter pylori

MS may develop after infections such as:

• measles
• canine distemper
• human herpes virus-6 (HHV-6)
• chlamydia pneumonia
• Epstein-Barr virus (EBV)

Treating MS and PsA

There’s currently no cure for either MS or PsA. But there are treatment options for each condition that can help you manage symptoms, slow disease progression, and prevent complications.

MS

The goal of MS treatment is to:

• manage your symptoms
• slow disease progression
• reduce the number and severity of relapses
• improve your overall quality of life

Treatment options for MS include disease-modifying therapies that can help reduce the number of relapses, delay progression to disability, and limit new disease activity. Disease-modifying therapies are available as infusions, injectables, and oral medications.

You may also be prescribed medications to treat specific symptoms of MS, such as muscle relaxants for spasms or antidepressants to manage emotional and mood changes.

PsA

The goal of PsA treatment is to:

• ease symptoms such as joint pain and stiffness
• slow disease progression
• prevent joint damage
• improve your overall quality of life

Treatment options for PsA include:

• Nonsteroidal anti-inflammatory drugs (NSAIDs): NSAIDs such as aspirin, ibuprofen, and naproxen can help reduce joint pain and swelling.
• Traditional disease-modifying antirheumatic drugs (DMARDs): Traditional DMARDs such as methotrexate reduce inflammation to help slow disease progression and prevent joint damage.
• Biologics: These are newer, more targeted DMARDs that target specific proteins in the immune system to prevent inflammation associated with PsA.
• JAK inhibitors: The newest and most targeted PsA treatment, JAK inhibitors block the proteins in the JAK-STAT signaling pathway to help decrease inflammation and lower disease progression.
• Surgery: Although not common, surgery may be required if you have a badly damaged joint or if medication does not help relieve your symptoms.

Lifestyle changes

People with MS and PsA can both benefit from making lifestyle changes.

Habits that can help you manage symptoms and improve overall quality of life include:

• eating a well-balanced diet
• getting regular physical activity
• practicing relaxation techniques or other methods to manage stress
• limiting alcohol
• not smoking
• getting plenty of rest

Takeaway

MS and PsA may affect your body in different ways, but the two conditions have shared characteristics, such as genetic and environmental risk factors.

It’s possible for people to have both MS and PsA. If you live with PsA or PsO, your doctor might recommend MS screening.