It's kind of like drying a wet sweater in the dryer, taking it out and struggling to put it on because it has so much static and it's also not the same size anymore. Because he was diagnosed with psoriasis at age 12, that's how Chris Pettit, 32, of Beaverton, Oregon describes his skin in the winter, "like it's shrunk because of the dryness — that it's too small for me."
The married father of three young boys is certain that when it's hotter in the Northwest and he gets to spend more quality time in the sun, "the dryness and redness both clear up for a while." Climatologists have confirmed that Oregon summers are getting hotter and drier, and they predict more rainfall for the other three seasons. That area of the country is historically known for copious amounts of rain.
"Rain and humidity haven't affected my psoriasis very much one way or the other," Chris told HealthCentral in a telephone interview. He's tried the gamut of treatments for his skin condition, including topicals and biologics — some just didn't work so well for him. Right now he's not using anything special, and taking it day by day.
"My legs aren't great right now, but the rest of me is OK," he says. "I tend to find whatever my wife has — creams or lotions — to use on my dry skin. I think, 'Well, this looks like it will work, and I will move on with my life.'"
There Is a Connection Between Weather and Psoriasis
Chris isn't imagining that weather affects his psoriasis. A letter published in 2013 in Occupational and Environmental Medicine summarized the results of a study on the effect of weather and both outdoor and indoor environmental factors on the clinical course of psoriasis.
Looking at two groups, one with only psoriasis and the other with psoriatic arthritis, the five authors found that "in most subjects," the problem improved in summer and worsened in winter, mainly because of sun exposure. They did note some worsening of symptoms in a small group of patients, due to sun. They also concluded that more attention should be paid to environmental factors so that the most appropriate therapy could be chosen for patients with psoriasis.
In the September 2015 Journal of the American Academy of Dermatology, the physician authors determined that winter flaring of psoriasis may be caused by the season's cold temperature, darkness, and low humidity, which they said can "increase skin permeability, epidermal thickening, and stimulate inflammatory mediator production," which means an overactive immune system. Summer improvement may be attributed to the sun's known immunomodulatory and bactericidal effects — modifying the immune system's function and also killing bacteria, they said.
To learn more about the connection between seasonal weather and psoriasis, HealthCentral spoke by phone to dermatologist Jerry Bagel, M.D., M.S., and founder of Windsor Dermatology and Psoriasis Treatment Center of Central New Jersey. He was the 2018 winner of the National Psoriasis Foundation's Excellence in Leadership Award.
The Psoriasis Lion in Winter
In general, people with psoriasis itch more in winter, confirms Dr. Bagel. "With less humidity in general, and forced air heat indoors, skin dries out and becomes itchier—and people scratch it," he says.
He also points to Koebnerization, a process named for a 19th-century dermatologist, during which the skin forms lesions at sites of trauma. This can happen if a person with psoriasis gets an insect bite or other even seemingly minimal injury the skin, like a scrape or burn — even a needle insertion from a vaccination.
"Then you scratch, which is another injury, and the psoriasis can get worse," he says.
The role of ultraviolet light can't be underestimated here, Dr. Bagel says. "It's known to decrease the proliferation of the epidermis, or outermost layer of skin. Psoriasis skin can grow more than seven times faster than normal, and it flakes because it doesn't 'mature' properly. You don't get as much UV light in winter because you don't get the benefit of as much sunlight."
What You Can Do for Psoriasis During the Harder Months
Be gentle: Don't take hot baths, but use lukewarm water, he says. Use a mild soap brand such as Dove or Cetaphil and then pat your skin dry very gently, without rubbing. Invest in a humidifier and consider having a contractor connect it to your heating system.
Be healthier: It's true that some illnesses seem to be more prevalent in winter, when you're more susceptible to infections, so try to stay healthy by giving your immune system extra attention, he says. Get recommended immunizations, take your daily multivitamin and if directed by your doctor, vitamin D.
A study in Reviews in Endocrine & Metabolic Disorders in 2017 confirmed that "significant associations between low vitamin D status and psoriasis have been systematically observed."
Eat wisely: Choose a more "Mediterranean-type" diet with fish, grains, healthy oils and fewer anti-inflammatory foods — and get enough exercise and enough sleep. Wash your hands frequently and correctly.
"Some infections can make psoriasis flare," says Dr. Bagel. "It's more important to treat those infections aggressively if you have psoriasis."
Lubricate skin: Finally, keep skin moisturized so it doesn't "crack," which could also cause Koebnerization, since a crack is an injury. Lotions have more water, while creams and ointments are more concentrated.
Psoriasis in Summer
Even though summer is "usually" better for psoriasis, a bad sunburn can not only be uncomfortable, but can also result in Koebnerization.
"Sunburn blisters may traumatize the skin," Dr. Bagel says, "in addition to increasing risk of skin cancer. Be smart and get some sun in incremental doses, and not when the sun is directly overhead."
Psoriasis in Spring and Fall
More pollen in the air may also trigger psoriasis flares. "We wonder if, in certain people with psoriasis, an immunologic response to pollen can cause this," he says. Pollen isn't just limited to spring. The dry Santa Ana winds that fuel forest fires in California can also blow pollen around in the fall.
Stress has also been shown to trigger psoriasis, and vice versa, so consider what situations stress you and make a plan for how to manage them. "For some people, going back to school in the fall may result in stress," Dr. Bagel says.
Psoriasis is an all-season skin condition, but with more knowledge, you can do your part to try and head psoriasis flares off at the pass, no matter what the weather forecast says.