There's no need to guess: Doctors and researchers haven't found links between the two problems. Here, four experts break down both conditions and explain what can trigger them.
Although psoriasis and allergies both involve your immune system, the causes for them aren't related.
An allergy happens when your immune system has a severe reaction to something that most people don't have a problem with, like pollen, pet dander, or certain foods.
Some people confuse psoriasis for allergies before they visit the doctor, because both conditions can cause itchy, red skin.
“A lot of people come in thinking they have allergic skin problems and when I see them, they've got psoriasis,” says Clifford Bassett, MD, an allergist and immunologist in New York City. "If you suspect it's one thing, it could be something else.”
So, get checked by a dermatologist if your skin itches or flakes, he says.
The Stress Factor
If you have psoriasis, stress may be partly to blame when the disease first appears and when it flares. Stress can also make your allergies act up.
“When you're having an allergic reaction, your body is working hard,” says Julie Pena, MD, a dermatologist in private practice in Nashville. “It's trying to fight something. When your body is going through stressful events, it alters the immune system. We know that stress can cause psoriasis to flare, [even] the internal stress of what your body is going through.”
Drugs May Have an Impact
Doctors have noticed that the drugs used to treat allergies can cause psoriasis to get better or worse, although it doesn't happen often.
The opposite can happen, too.
Some people's psoriasis reportedly improves once they get treated for their hay fever, says Abby S. Van Voorhees, MD, director of the Psoriasis and Phototherapy Treatment Center at the Hospital of the University of Pennsylvania. “It's hard to know, was that just a coincidence?”
Also, people who take psoriasis drugs that turn down the immune system might find that they have fewer allergies, "but this isn't proven," Pena says.
Blowin' in the Wind?
Some doctors say that people who have psoriasis and allergies sometimes may have flares of both at similar times of the year. But they let their patients know that the seasons or the weather, not the health conditions themselves, are to blame.
Winter temps or dry air might make some people's allergies worse, and that kind of weather can make psoriasis flare, too, Benabio says.
Tips to Avoid Flares
Psoriasis can't make allergies worse and vice-versa. But you can lower your chances for a flare of either if you avoid problems that impact both:
- Ease stress. It can impact both conditions, Bassett says. Try to relax or avoid drama at home or work.
- Manage itchy skin. Psoriasis can flare in places where your skin is damaged. If you have hives or an allergic reaction and you scratch that spot too much, the damage your nails do can make your psoriasis worse. Try over-the-counter cortisone cream, or ask your doctor to prescribe a stronger version.