Psoriatic arthritis (PsA) is a type of autoimmune disease that may have an association with lymphoma, the most common type of blood cancer. However, research on the connection is not consistent.

Autoimmune diseases are when the immune system attacks healthy cells in your body. There are many different types of autoimmune diseases, from ulcerative colitis and Crohn’s disease to psoriasis and PsA.

For example, research suggests that people with some autoimmune conditions like rheumatoid arthritis (RA), lupus, and Sjögren disease may be at a higher risk of developing lymphoma than people who don’t have these conditions.

While there’s some evidence that this also includes psoriasis, the link between lymphoma and PsA isn’t as definitive.

Read on to see what the research so far says about the risk of lymphoma in people with psoriatic disease.

Some research suggests that lymphoma risk is anywhere from 1.3 to 2 times higher in people who have psoriasis than in the general population. One analysis of 112 studies found a higher risk of lymphoma and several other cancers in people with psoriasis than in those without this disease.

Research most often links psoriasis to an increased risk of T-cell lymphoma, which is a type of non-Hodgkin’s lymphoma.

It’s unclear whether psoriasis itself raises the risk of T-cell lymphoma. It may be that this cancer is sometimes misdiagnosed as psoriasis. The two diseases cause similar symptoms, including scaly, itchy patches of skin. A skin biopsy may be needed to tell them apart.

About 30% of people with psoriasis also have PsA. This means that some people with both conditions may be at a higher risk of getting lymphoma. That said, research hasn’t yet found a direct link between this cancer and PsA.

Researchers don’t know exactly why people with autoimmune diseases like psoriasis and PsA are at higher risk of lymphoma. Studies point to a few possible reasons for the connection.

An overactive immune system

Psoriasis and PsA are autoimmune disorders, which are when your immune system overreacts against your own body. Immune system cells attack the joints and skin just as they usually attack bacteria and other potentially dangerous invaders.

Lymphoma starts in a type of immune cell called a lymphocyte. The overactive immune system in people with psoriatic conditions may cause lymphocyte cells to divide faster than usual, leading to cancer.

Immune-suppressing drugs

Certain drugs that treat psoriasis and PsA work by tuning down your body’s immune system response so that inflammation can’t damage your joints and skin. A weakened immune system could also increase the risk of lymphoma.

For example, some research suggests that people who take biologic drugs called TNF inhibitors may be more likely to have lymphoma than people who don’t take these medications. Doctors sometimes prescribe TNF inhibitors to people with PsA.

Chronic inflammation

Inflammation isn’t always a bad thing. When you’re injured, it can help your body heal. But when inflammation is chronic, like in psoriasis and PsA, it can damage cells.

Long-term (chronic) inflammation can disrupt DNA, the genetic material inside cells. DNA changes can cause cells to divide irregularly and become cancerous.

Shared risk factors

Some of the same factors that put you at risk of psoriasis and PsA may also increase the risk of lymphoma, including:

  • being overweight (body mass index [BMI] of 25 to 29.9)
  • having obesity (BMI greater than or equal to 30)
  • having metabolic disorders
  • smoking (if applicable)
  • drinking too much alcohol (if applicable)

There might be other risks linking the two diseases that researchers don’t know about yet.

Can psoriatic arthritis cause swollen lymph nodes?

PsA is an autoimmune condition that can sometimes cause your lymph nodes to swell. This is a sign that your immune system is overactive.

Note, however, that just having swollen lymph nodes does not automatically mean you have lymphoma, despite the similarities in the words. While swollen lymph nodes can be a sign of cancer, they can also occur from the autoimmune disease itself or from other causes like an infection.

What cancers besides lymphoma are linked to psoriasis?

People with psoriasis also have a higher chance of developing carcinoma, melanoma, lung cancer, colon cancer, rectal cancer, and bladder cancer, according to a 2020 review of 365 studies.

What other skin conditions are associated with lymphoma?

Lupus, which can affect the skin, is a risk factor for lymphoma. Another skin condition is Sézary syndrome, which is a type of cutaneous T-cell lymphoma.

Does T-cell lymphoma look like psoriasis?

Both cutaneous T-cell lymphoma and psoriasis can present as scaly plaques or patches on the skin.

Research has not yet proven the link between psoriasis, PsA, and lymphoma. And even if having psoriatic disease does make you more likely to get this cancer, your overall risk is small.

Risk increases if you have psoriasis or PsA and other conditions linked to lymphoma, such as Sjögren disease.

It’s still a good idea to be aware of your cancer risk, especially if you also have a strong family history of lymphoma or other known risk factors. If you have psoriasis or PsA, it’s good to know lymphoma symptoms like:

  • swollen glands
  • unexplained weight loss
  • night sweats
  • tiredness that doesn’t go away
  • shortness of breath

Report these and any other unusual symptoms to your doctor. You can have tests to rule out or diagnose cancer.

Also, consider having a conversation about your medications with the doctor who treats your psoriatic disease. Try to find out whether your treatment might put you at increased risk of lymphoma. If so, determine whether you need extra screening.