People with psoriasis are up to three times more likely to develop lymphoma than the general public — but there is more to the story. A psoriasis diagnosis does not guarantee you will develop lymphoma. However, it’s essential to be aware of the possible connection so you can discuss it with your health care provider and be on the lookout for symptoms. As for psoriatic arthritis (PsA) and lymphoma, there doesn’t appear to be a connection.

What Is Lymphoma?

Lymphoma is a type of cancer that affects the lymphatic system, which is part of the immune system. The lymphatic system includes the lymph nodes, bone marrow, spleen, and thymus gland. There are more than 70 types of lymphoma, but the two main types are Hodgkin and non-Hodgkin lymphoma.

Common signs and symptoms of lymphoma include:

• Swollen lymph nodes in your neck, armpits, or groin
• Unexplained weight loss
• Fatigue
• Itchy skin
• Shortness of breath
• Chest pain
• Coughing
• Abdominal pain or swelling

Keep in mind that having any or all of these symptoms doesn’t mean you have lymphoma. These are mostly general symptoms that can have multiple causes. Talk to your doctor about any changes in your health.

Psoriasis and Lymphoma

Psoriasis is an autoimmune disease that affects approximately 7.5 million people in the United States. The condition is characterized by raised, scaly patches (plaques) commonly found on the knees, elbows, and scalp.

Research published in the Journal of the American Academy of Dermatology has found that people with psoriasis have an increased risk of developing lymphoma, and a 2019 study determined that cancer is a comorbidity in people with psoriasis. Comorbidity means two or more diseases are related or likely to occur together, not that one causes the other. Psoriasis comorbidities include psoriatic arthritis, cardiovascular disease, obesity, hypertension, and diabetes.

Psoriatic Arthritis and Lymphoma

Psoriatic arthritis is a chronic (ongoing) disease that affects approximately 1 in 3 people with psoriasis. PsA causes inflammation and primarily affects the joints and areas where tendons and ligaments connect to bones. While these two conditions are related — PsA is a common comorbidity of psoriasis — they don’t appear to share the same connection to lymphoma.

An analysis published in 2020 found that PsA is not associated with an increased risk of cancer, including lymphoma. However, the authors noted that more research is needed. If you have PsA and swollen lymph nodes, talk with your doctor so they can investigate further.

What Causes Lymphoma With Psoriasis?

Although it’s unclear exactly why people with psoriasis have an increased risk of lymphoma, some health experts suggest that an overactive immune system, certain medications, and lifestyle factors may play roles.

Immune System

Autoimmune diseases like psoriasis, rheumatoid arthritis, and systemic lupus erythematosus (also called lupus) occur when the body can’t distinguish between its own cells and foreign cells. The American Cancer Society lists autoimmune diseases as risk factors for both Hodgkin lymphoma and non-Hodgkin lymphoma. One explanation for this could be an overactive immune system.

When the body mistakenly attacks healthy tissue in people with psoriasis and other autoimmune diseases, white blood cells called lymphocytes become overactive and trigger inflammation. Lymphocytes are also where lymphoma develops. Some health experts suggest that the chronic inflammatory response in people with autoimmune diseases could play a role in the genetic mutations that cause lymphoma.

Other diseases that cause chronic inflammation, like Crohn’s disease and rheumatoid arthritis, have also been linked to an increased risk of cancer.

Medications

Immunosuppressive drugs are used to treat psoriasis and other autoimmune diseases. They’re also prescribed after organ transplants. These medications calm the immune system, which can be helpful for relieving from psoriasis symptoms or helping the body to accept a new organ after a transplant. However, immunosuppressives can also increase a person’s risk of lymphoma and other types of cancer. By suppressing the immune system, they leave the body open to attack.

Methotrexate (Trexall), a drug used to treat psoriasis, has also been linked to an increased risk of developing lymphoma. Methotrexate suppresses the immune system to slow the overproduction of skin cells in people with moderate to severe psoriasis.

Taking methotrexate and other immunosuppressive drugs doesn’t mean you’ll develop lymphoma. Discuss the risks and benefits of these medications with your health care provider.

Lifestyle Factors

Psoriasis and lymphoma share a few risk factors that could contribute to the connection between the two conditions. These risk factors include:

• Smoking
• Increased alcohol use
• Metabolic syndrome

Metabolic syndrome is a combination of risk factors that are often preventable, like excess belly fat, high blood pressure, high blood sugar levels, low high-density lipoprotein (“good”) cholesterol, and increased triglyceride levels. Some health experts recommend that people with metabolic syndrome make lifestyle changes associated with better overall health. These healthy habits include:

• Avoiding tobacco
• Increasing physical activity
• Eating healthy foods

If you have questions about lifestyle changes to improve your well-being and reduce your risks of cancer and chronic diseases, talk with your doctor.

How Psoriasis and Lymphoma Affect Members’ Lives

Although a psoriasis diagnosis doesn’t guarantee a lymphoma diagnosis, it’s natural to be concerned about your health. Comments from members of MyPsoriasisTeam suggest that they’re most worried about psoriasis treatments that could potentially lead to cancer:

• “I am worried about the increased cancer risk with biologics and being able to fight infections.”
• “I am afraid of biologics.”
• “I have non-Hodgkin lymphoma, so I am pushing for a new drug.”
• “My psoriasis is mostly on my legs. I have non-Hodgkin lymphoma, so I can’t take most biologics.”
• “Unfortunately, I can’t be on any biologic medication because of my history of non-Hodgkin lymphoma.”
• “I have psoriasis, and my doctor wants me to take something for it, but I am in remission from lymphoma and don’t want to take anything that could cause lymphoma.”

When biologic agents were introduced, some studies from the Arthritis Foundation suggested a potential connection between biologics and cancer. However, recent studies have dismissed that theory. A 2016 study from the journal Annals of Rheumatic Diseases of more than 15,000 people who took biologics for rheumatoid arthritis found no increased risk. If you have questions about biologics and lymphoma, talk to your doctor.

“Don’t be afraid of biologics,” said one MyPsoriasisTeam member. “They actually made my life much better.”

Should You Worry About Lymphoma?

According to the American Cancer Society, the risk of developing non-Hodgkin lymphoma is 2.1 percent for the general population. For Hodgkin lymphoma, the risk is less than 1 percent. Although having psoriasis increases your odds, the risk is still small.

While it’s good to be aware of the connection between psoriasis and lymphoma, don’t let that knowledge cause you unnecessary stress or anxiety. Familiarize yourself with lymphoma symptoms, tell your doctor about any changes to your health, ask about the risks and side effects of your psoriasis treatments, stay up to date with recommended health screenings, and find a supportive community.

Talk With Others Who Understand

MyPsoriasisTeam is the social network for people with psoriasis and psoriatic arthritis and their loved ones. On MyPsoriasisTeam, more than 115,000 members come together to ask questions, give advice, and share their stories with others who understand life with psoriasis and psoriatic arthritis.

Are you living with psoriasis and lymphoma? Share your experience in the comments below, or start a conversation by posting on your Activities page.