Psoriasis is an autoimmune disease that causes plaques, which are itchy or sore patches of thick, red, dry skin.
While any part of your body can be affected, psoriasis plaques most often develop on the elbows, knees, scalp, back, face, palms, and feet.
Like other autoimmune diseases, psoriasis occurs when your immune system — which normally attacks infectious germs — begins to attack healthy cells instead.
According to the National Psoriasis Foundation, about 7.5 million people in the United States have psoriasis, with the disease affecting Caucasians more than any other race. (1)
The disease occurs about equally among men and women. According to the National Institutes of Health (NIH), it is more common in adults, and you are at a greater risk for the disease if someone in your family has it. (2) A study published in September 2016 in the journal PLoS One concluded that “interactions between particular genes as well as genetic and environmental factors play an important role” in the disease’s development. (3)
People with psoriasis generally see their first symptoms between ages 15 and 30, although developing the disease between 50 and 60 years of age is also common. (4)
“The biggest factor for determining prognosis is the amount of disease someone has,” says Michael P. Heffernan, MD, a dermatologist at the San Luis Dermatology and Laser Clinic in San Luis Obispo, California.
What Are the Symptoms and Complications of Psoriasis?
Psoriasis plaques can range from a few spots of dandruff-like scaling to major eruptions that cover large areas. The disease’s symptoms and appearance vary according to the type and severity of psoriasis.
For some, psoriasis can clear up for months or even years at a time. This is known as remission. (5)
Others experience psoriasis flares, or flare-ups, in cyclical patterns. For instance, the disease may improve in the summer and worsen in the winter.
Psoriasis is associated with a number of health conditions, including high blood pressure, high cholesterol, diabetes, and depression. (6)
“Over the last few years, we’ve seen that maybe psoriasis plays a more integral part in metabolic syndrome, a collection of symptoms that can lead to diabetes and heart disease,” says Erin Boh, MD, chairman and professor of dermatology at Tulane University in New Orleans and a member of the National Psoriasis Foundation board.
It is estimated that up to 30 percent of people with psoriasis will also develop psoriatic arthritis, an autoimmune disease that affects the joints. According to the National Psoriasis Foundation (NPF), psoriasis occurs before joint disease in 85 percent of psoriatic arthritis patients. (7)
The risks for psoriasis-related complications are greater the younger a patient is when diagnosed and the more severe the psoriasis. (8) Anyone with psoriasis should be aware that they are at risk for comorbid conditions and should monitor their overall health accordingly.
What Causes Psoriasis, and How Is It Treated?
Psoriasis, in general, is a genetic condition passed down through families. “It’s likely that multiple genes need to be affected to allow psoriasis to occur, and that it’s frequently triggered by an external event, such as an infection,” says James W. Swan, MD, professor of dermatology at the Loyola University Stritch School of Medicine in Maywood, Illinois.
According to the NPF, at least 10 percent of people inherit genes that could lead to psoriasis, but only 3 percent or less actually develop the disease. (9) For this reason, it is believed that the disease is caused by a combination of genetics and external factors or triggers.
While psoriasis cannot be cured, there are effective options for treating it. Medication ranges from over-the-counter or prescription topicals to biologic drugs that target parts of the immune system. Another treatment option is light therapy, also known as phototherapy, which targets the skin with ultraviolet rays of light. (10)
The right combination of treatments may be determined by what triggers cause a patient’s psoriasis to flare up. Psoriasis flares may be triggered by:
Stress
Stress is a major trigger for some people with psoriasis, either causing psoriasis to flare up for the first time or to make it worse after you’ve been diagnosed. (11)
“Psoriasis is very stress-dependent. It flares very easily when patients are under stress, and it tends to improve when they’re relaxed,” says Vesna Petronic-Rosic, MD, dermatologist and associate professor of medicine at the University of Chicago Medicine in Illinois. Stress management techniques, such as exercise, yoga, and meditation, may help manage psoriasis symptoms.
Cold Weather
A trip to the Caribbean might be a good idea during the winter months if you have psoriasis and live in a cold climate, because the sun’s ultraviolet light turns off the skin’s immune system, which is overactive in people with psoriasis. Check with your dermatologist before traveling for sun safety skin tips, and limit your daily exposure to no more than 10 minutes of direct sunlight.
Dry Skin
Anything that injures the skin can cause a psoriasis flare, including excessively dry skin.
The solution: Keep your skin moisturized. If you’re allergic to the fragrances in moisturizers, use a product that’s fragrance-free to avoid a rash.
Vaccinations
As with dry skin, puncturing the skin during a vaccination may cause a psoriasis flare, but that’s no reason to skip a needed shot. (12)
One thing to keep in mind: If you’re on a potent psoriasis medication that suppresses your immune system (such as a biologic treatment), you shouldn’t take a live vaccine. Your body may not be able to fight off a live virus because of the medication you’re taking. In that case, ask your doctor for a vaccine that contains a deactivated virus.
Beta-Blockers and Lithium
Beta-blockers to treat high blood pressure, and lithium for a mental disorder, can make psoriasis worse. (13, 14)
If you have high blood pressure, your doctor may be able to switch your medication to another drug that won’t affect the psoriasis. If you’re taking lithium, your dermatologist may consider having you try light treatment or a topical therapy for psoriasis.
Upper-Respiratory Infections
Colds and other infections, especially strep throat, activate the immune system and can cause psoriasis to flare. (15) If you have psoriasis and develop a sore throat, get it treated and be sure to have a culture taken to check for strep. Long-term antibiotics may be an option for someone who has psoriasis and frequent sore throats.
Smoking
There’s some evidence that smoking can make psoriasis worse. According to a study published in March 2012 in the American Journal of Epidemiology, smokers have almost double the risk of developing psoriasis compared with people who’ve never smoked. (16) In a smaller study published in February 2016 in the International Journal of Dermatology that looked at twins, heavy smokers were more than twice as likely to have psoriasis. (17)
Diet
Studies haven’t shown any beneficial effects of taking nutritional supplements for psoriasis, but avoiding certain foods may reduce inflammation and help with psoriasis. Additionally, studies have shown that many people with psoriasis may also have a gluten sensitivity, and eating a gluten-free diet can help reduce psoriasis symptoms. (18) In general, if you find that a certain food makes the psoriasis worse, try to avoid it.
Alcohol
For some people with psoriasis, having more than one or two drinks a day has been shown to cause psoriasis flares, but the association is not a strong one. Flares from alcohol use could also be linked to psychological stress.
What Kind of Psoriasis Is It?
There are five types of psoriasis, yet people most often have only one type of psoriasis at a time. Each type has its own set of symptoms.
Most types of psoriasis go through cycles, flaring for a few weeks or months, then subsiding for a time or even going into complete remission.
Plaque Psoriasis
Also called psoriasis vulgaris, plaque psoriasis is the most common form of the disease. It appears as raised, red plaques covered with a silvery white buildup of dead skin cells, or scale. The itchy, painful plaques can crack and bleed, and commonly affect the scalp, knees, elbows, back, hands, and feet.
Guttate Psoriasis
Often beginning in childhood or young adulthood, guttate psoriasis is the second most common type of psoriasis. Nearly 10 percent of people who get psoriasis develop guttate psoriasis, according to the National Psoriasis Foundation (NPF).
Inverse Psoriasis
Also known as intertriginous psoriasis, inverse psoriasis causes red lesions in skin folds of the body that may look smooth and shiny. These lesions can occur on the genitals or in areas near the genitals, like the upper thighs and groin. It’s common for people with inverse psoriasis to have another type of psoriasis somewhere else on their body at the same time.
Pustular Psoriasis
This causes white blisters of pus that surround red skin, often on the hands or feet. The pus consists of white blood cells. When pus-filled bumps cover the body, you may have bright-red skin and feel ill, exhausted, have a fever, chills, severe itching, rapid pulse, loss of appetite, or muscle weakness.
Erythrodermic Psoriasis
This is a dangerous and rare form of the disease characterized by a widespread, fiery redness and exfoliation of the skin that causes severe itching and pain. Erythrodermic psoriasis occurs once or more in 3 percent of people with psoriasis, according to the NPF.
Is It Scalp Psoriasis or Dandruff?
More than half of all people with psoriasis have scalp psoriasis, according to the NPF. (19) Red, itchy plaques can extend beyond the hairline onto the forehead, neck, and around the ears.
“Most people with scalp psoriasis have it on other parts of their body as well,” says Dina D. Strachan, MD, a dermatologist and assistant clinical professor of dermatology at NYU Langone Medical Center in New York City.
Scalp psoriasis is sometimes confused with seborrheic dermatitis, or dandruff. According to Dr. Strachan, dandruff — which causes a flaky, itchy scalp without signs of inflammation — tends to itch more than scalp psoriasis. “It has a greasy-appearing yellow scale,” Strachan says. “In contrast, psoriasis — whether it’s on your scalp or any other body part — tends to have a thick, silvery scale.”
Is It Psoriasis or Eczema?
Because psoriasis can look like other skin conditions that cause itchy, scaly rashes with inflammation, it is often confused with various disorders. These may include common skin conditions, such as eczema. (20)
Like psoriasis, eczema is a very itchy skin condition. Scratching causes redness and inflammation of the skin, leading to a worsening of the eczema. Scratching can also cause a secondary bacterial infection.
Eczema is not a specific disease, but rather a term referring to a group of rash-like conditions. The most common type of eczema is caused by a reaction to irritants, like detergents, soaps, or household cleansers.
Psoriasis can also resemble and be confused with other conditions, including the fungal infection known as ringworm.
What Resources Can Help You Manage Psoriasis?
Individuals with psoriasis can find significant educational and emotional support through online resources.
From psoriasis organizations to online communities, these sites deliver the latest news on medication and therapies, information on clinical trials, and access to patient advocacy groups.
Founded in 1966, the National Psoriasis Foundation (NPF) offers research news and advice on managing psoriatic disease, as well as access to online support communities.
According to survey results published in the journal Archives of Dermatology, psoriasis online communities offer a valuable resource for information and psychological and social support. (21) Almost half of respondents reported improvements in their overall quality of life, and 41 percent said their symptoms were less severe after joining an online community.
Online resources also help friends and family of people living with psoriasis. In a study published in 2014 in the Journal of the American Academy of Dermatology, which looked at the burden of psoriasis on people living together, almost 90 percent of participants noted an impact on their own quality of life in addition to their loved one with the disease. (22) “To help a loved one manage a disease, you first have to understand it,” says Kenneth Beer, MD, a dermatologist in West Palm Beach, Florida.
