Allergies and Psoriasis: Is There a Connection?

What Are Allergies, Exactly?

There are a few different types of common allergies. Seasonal allergies are environmental allergies that make your nose runny and itchy from pollen, weeds, and grasses. Food allergies are due to food sensitivities—consuming the foods you’re allergic to may lead to a whole-body reaction including itchy skin, hives, and, in severe cases, swelling of throat or tongue, even death. Skin allergies are caused by allergens touching the skin resulting in itchy skin and an eczema-like rash within days or weeks of exposure.

Is There a Connection Between Allergies and Psoriasis?

It makes perfect sense that someone with both psoriasis and allergies might wonder if the two are connected. Could your allergies be contributing to your psoriasis symptoms, or the other way around? The answer is: not really.

“It is a common misconception that psoriasis and allergies are linked,” says Ife J. Rodney, M.D., a board-certified dermatologist at Eternal Dermatology in Fulton, Maryland. “There is no evidence to prove this connection.” In a recent article published in Contact Dermatitis, people with psoriasis had lower rates of skin allergies (allergic contact dermatitis) than those without psoriasis did.

Rodney explains that psoriasis is an immune-mediated inflammatory condition impacting the skin and joints, and that there is also a genetic connection, since the condition often runs in families.

“On the other hand, allergies are the body’s response to external factors, like certain foods, dust, pollen, or ingredients in skincare products,” Rodney says. “The average person is more likely to develop allergies than [they are to have] psoriasis.”

In other words: One doesn’t cause the other—or worsen the other, either. The only similarity they share, she said, is that both often involve a ramped-up immune system.

Yeah, But Allergies Could Make Psoriasis Worse, Right?

In a way, allergies can make psoriasis worse. But Rodney explains that it’s not so much that the allergy is causing the psoriasis to flare. “Allergies have no real direct impact on psoriasis,” she says, but, there can be an indirect impact. Stress is a common trigger for psoriasis, and allergic reactions can cause quite a bit of stress.

“So, it’s not unheard of for someone with both allergies and psoriasis to fall into a cycle of an allergic reaction, stress, and then a psoriasis flare-up,” says Rodney.

Susan Bard, M.D., a board-certified dermatologist of Vive Dermatology in Brooklyn, New York, agrees, adding that rubbing or scratching areas of skin affected by allergies may trigger a psoriasis flare in that area, too. This is due to the Koebner phenomenon, in which areas of skin injury may result in new psoriasis plaques.

Plus, sometimes, allergic contact dermatitis may look like psoriasis. In someone with psoriasis, an itchy rash in a new area may be assumed to be psoriasis, when it’s actually due to a skin allergy. Even though the treatments are very similar, topical steroids will relieve symptoms of both conditions.

It’s best to get the correct diagnosis. If you find out that you’re allergic to something, you can avoid it in order to clear up an allergic contact dermatitis rash completely. But psoriasis tends to stay around for a long time.

Allergy Testing and Psoriasis

Given all this, you might wonder if people with psoriasis should get tested for allergies. The answer is: maybe.

“Anyone should consider getting allergy tested when their allergies are bothersome to their life,” says Bard.

It’s important to know, though, that despite what you might expect, allergy testing does not identify psoriasis triggers. In fact, something you’re not allergic to may trigger your symptoms.

“Psoriasis flare-ups are an autoimmune response, can happen at any time, and are unrelated to allergic reactions,” Bard says. “If you believe you have an allergy, the symptoms will be different from that of a psoriasis flare. Really, an allergy test only helps to identify possible allergens.”

Still, if you have both allergies and psoriasis, treating both may be your best bet for finding relief.

“Remember that it is possible to have an allergic reaction at the same time as a psoriasis flare,” says Rodney. “If you think you have both of these conditions active at the same time, it's best to see your dermatologist. They can help you figure out exactly what's going on.”

Whether or not you have allergies, if you’re looking to help prevent psoriasis flares, it’ll likely be most helpful to take steps to reduce inflammation.

“When there is inflammation in the body, the immune system is more likely to produce the cells that cause psoriasis flares,” explains Rodney. “So, it’s important to focus on stress-reduction techniques and to look out for other psoriasis triggers like sunburn, cuts and bruises, and certain immune-related illnesses.”

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