Why Do I Have Psoriasis? 3 Common Causes

By Leah Campbell
September 01, 2021

It’s estimated that more than 8 million Americans—and some 125 million people worldwide—have psoriasis, according to the National Psoriasis Foundation. If you’re one of them, you probably want to know: Why me? This is a natural question to ask when diagnosed with a chronic health condition. As human beings, we want answers.

But when it comes to psoriasis, unfortunately, the why isn’t always clear. “Despite several decades of research, the exact cause of psoriasis is still unknown,” says Nikki Hill, M.D, a board-certified dermatologist and founder of the Skin of Culture and Hair Center in Atlanta, Georgia. Still, science has shed some light on factors that can increase one’s likelihood of having the condition. Here’s what we know about what causes—and doesn’t cause—psoriasis.

Genetic Likelihood

To begin with, Hill says, “We do know that the immune system and genetics are key contributing factors.” This much becomes obvious when you look at the ethnic breakdown of psoriasis cases, with the vast majority (87 percent) occurring among Caucasian patients. African Americans make up only 2 percent; Asian Americans make up another 2 percent, and Native Americans comprise only 1 percent of psoriasis cases.

Researchers believe that genetics play a role in how the immune system is activated by psoriasis. So far, they’ve discovered 25 different genes that increase a person’s likelihood of developing the condition. But know that carrying the genes for psoriasis does not mean one will automatically develop the condition. A person can have a strong family history and never display symptoms of psoriasis themselves. In fact, it’s believed that at least 10 percent of the general population has the genetic makeup linked to the development of psoriasis, but only 2% to 3% will ever develop symptoms of the disease.

No one can say for sure why that is. The main takeaway is that the development of psoriasis may be due to a combination of genetics and environmental triggers—and without both, the condition never occurs.

The Role of Triggers

Many people have no idea they’re predisposed to the condition, then one day find themselves covered in scales after experiencing a stressful time, an injury, or an illness such as strep.

Psoriasis “can be unmasked by a variety of triggers, such as physical or emotional stressors, including certain infections,” explains Susan Bard, M.D., board-certified dermatologist at Vive Dermatology in Brooklyn, New York. “The triggers are not the cause. There is nothing that one did or did not do that caused them to have psoriasis.”

The genetic predisposition simply makes people more susceptible to those triggers, Bard says.

The National Psoriasis Foundation identifies medications such as Lithium, Inderal (a blood pressure medication) and antimalarials as other potential triggers of psoriasis. And while they haven’t been proven scientifically, some people suspect their own psoriasis may have been triggered by allergies, diet, or weather changes.

No matter the potential trigger, it’s important not to blame yourself. “There is no known way to cause or prevent disease development if one is prone,” says Bard. “The disease may flare and remit or may be chronic and progressive.”

You can help yourself, though, by paying attention to what potential triggers in your own life may be contributing to your symptoms. “It is best to avoid triggers to prevent flares,” Bard explains. Together with your dermatologist, you can work to identify your own personal triggers.

The Nervous-System Connection

The National Institutes of Health (NIH) has reported on potential contributing factors related to the nervous system. Stress is a known trigger for psoriatic symptoms, and local anesthetics have been shown to reduce inflammation. Working with this knowledge, researchers hypothesized that pain-sensing neurons may play a role in psoriasis flares. They removed those neurons from mice, and in doing so discovered that the mice were less responsive to a molecule that they later discovered contributed to the development of psoriasis lesions.

This research is still in its infancy, but scientists are hopeful that by gaining a better understanding of the role pain receptors play in psoriasis, they may be able to explore a whole new realm of treatment possibilities.

Moving Forward With or Without Answers

In the end, it won’t help to dwell on what caused your psoriasis. Instead, focus on taking charge of your health and managing your condition. Hill says it’s important to understand that there are treatments available and that you’re not alone in this journey.

Once you’ve been diagnosed, you’ll have the opportunity to work closely with your dermatologist to develop an effective treatment plan that will give you some relief.

Hill says it can be empowering for patients to learn that psoriasis is manageable, adding: “Living with it will not define who you are or what you can do.”

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