Can psoriasis affect your kidneys?

Psoriasis affects nearly 7.5 million people in the U.S., according to the National Psoriasis Foundation (NPF). For people with this chronic skin condition, which causes scaly and itchy skin patches all over the body, the problems it causes are beyond skin deep.

The NPF reports that psoriasis can be associated with an increased risk of diabetes, heart disease and even depression. And now a new study also finds a link between moderate to severe psoriasis and kidney problems.

“Psoriasis is an autoimmune disease of the skin that causes inflammation throughout the entire body,” says Dr. Aamir Memon, nephrologist on staff at Advocate Sherman Hospital in Elgin, Ill. “When you have an autoimmune disease, you have antibodies in your blood, which can deposit anywhere in the body, such as your heart and kidneys. The increased inflammation increases the risk of atherosclerosis (hardening of the arteries) and organ damage.”

The study, featured in the journal BMJ, analyzed 144,000 people with psoriasis and a control group of 690,000 people without psoriasis for seven years. Researchers concluded that people with moderate and severe psoriasis were more likely to develop chronic kidney disease than the control group.

Moderate psoriasis is defined as three to 10 percent of skin area affected and severe psoriasis is defined as more than 10 percent. Participants in the study defined as having severe psoriasis received treatment such as phototherapy, oral or injectable medications.

People with severe psoriasis were twice as likely to develop chronic kidney disease and four times as likely to need dialysis due to end-stage kidney disease. The study took into account known risk factors of chronic kidney disease such as diabetes, high cholesterol and high blood pressure.

Despite adjustments for these risk factors, psoriasis remained an independent risk factor. The study also found that the risk of chronic kidney disease increases with age among those with severe psoriasis.

According to Dr. Memon, many patients with moderate to severe psoriasis take medications like Cyclosporine or Methotrexate as treatment. However, side effects from these medications include kidney problems.

As a result, Dr. Memon says it can be difficult for physicians to evaluate whether medication or other medical conditions are causing the kidney disease.

“This study proves that there is still an association between psoriasis and kidney disease even among patients who do not take these medications,” he says.

With these study findings, doctors must determine the best course of action for managing the inflammation caused by psoriasis.

“Since psoriasis has effects on the kidneys, it would intuitively make sense to control the inflammation to prevent further worsening of the kidneys,” Dr. Memon says. “Further studies are needed to evaluate if that is the case and as to what medications are best to decrease inflammation and prevent or halt kidney disease.”