Ask a psoriasis patient whether stress affects his or her psoriasis, and the answer is almost always a resounding yes. There usually seems to be a stressful event that one can recall had happened before a psoriasis flare. And stressful times seem to make psoriasis worse.

Or tell someone you have psoriasis, and in a surprisingly high proportion of cases, the person will proceed to tell you some food that they are certain is triggering your psoriasis. Tomatoes! Gluten! Sugar!

But the actual scientific evidence proving a causal relationship – that high stress leads to psoriasis flares in those predisposed to get psoriasis, or that it leads to worsening of existing psoriasis – is not strong. And the actual evidence that any particular food triggers psoriasis is almost nonexistent.

So why such focus on those issues? Part of it is probably the human desire to believe that everything is within our control. Having a faulty immune system that can be treated but not cured is not a message we can easily accept. Human nature wants to believe it’s simply a matter of finding our triggers.

Of course, another reason it gets so much attention is because a lot of people have a financial stake in convincing you that your psoriasis is due to the things you eat (or obscure nutrients you are not eating), or your failure to practice mindfulness. There is a seemingly endless supply of phony cures peddled on YouTube, in message boards, in books, via Google ads, and in dietary supplement promotions. It’s lucrative to give desperate people false hope. (It’s also, well, deplorable.)

Still, it is our hunch that stress can worsen a psoriasis flare, and that severe stress can trigger a flare. There is simply a dearth of very solid research on the issue. (It’s also our hunch that not getting enough sleep, among other things, can worsen a psoriasis flare.)

As for diet, there are a few things we are learning that are backed up by pretty good science: excessive alcohol consumption, and tobacco use, can make psoriasis worse, as can obesity.

On the other hand, a 2019 study examined gluten intake in 85,000 women nurses with psoriasis or psoriatic arthritis who were tracked over more than two decades. They self-reported dietary habits every two years. (Self-reported data is not considered highly reliable, but at least it was nurses who presumably took the task seriously and worked to get it right.) The results showed that gluten intake had no impact on whether someone developed psoriasis or psoriatic arthritis over that time. (If you have celiac disease and eat gluten, you can develop a skin condition that mimics psoriasis. So someone triggered by gluten might have celiac disease rather than gluten-triggered psoriasis.)

We believe that too much attention is paid to the roles of stress and diet in psoriasis, at the expense of more important conversations that could better-improve patient lives. What’s more, some of the media discussions about stress and diet as triggers for psoriasis almost have a “blame the victim” feel; as if people could control their psoriasis if they would just learn to handle stress better or cut out junk food.

“That three year-old with psoriasis should have done more yoga!” As one prominent dermatologist once put it: “I have treated both CEO’s and entry-level employees, and everyone has stress. So it’s not that useful to focus on it.”

Or consider a different terrible disease, Multiple Sclerosis (MS). The role of stress in MS is in a surprisingly similar place as the role of stress in psoriasis: MS patients will tell you that stress seems to play a role, but the scientific proof is such that a leading MS group refers to stress impacting MS merely as “considered possible.” But does the media focus on the stress angle as frequently with MS as with psoriasis?

If some of the attention given to stress and diet were directed instead to educating psoriasis patients to be vigilant in avoiding strep throat, and to always taper steroids like prednisone rather than cutting them out cold turkey, that would be a net positive for those with psoriasis.

But more generally, the constant focus on stress and diet diverts attention from delivering important news that has still not reached everyone with psoriasis: There are now psoriasis treatments that can help almost everyone. That is far more important than another piece about nightshade vegetables (see below).

It is an exciting time for psoriasis patients. Effective treatments have multiplied. That is where our focus should be.

What do you think? Are we out to lunch on this one? (It wouldn’t be the first time.) Let us know and we will keep our minds open to other possibilities.

Further reading:

Despite Appearing Obvious, Link Between Stress and Psoriasis Is Still Not Well Understood

The Cleveland Clinic on Nightshade Vegetables

[Last updated 6-2-2020]