What Is psoriasis?
Psoriasis is a disease in which red, scaly patches form on the skin, typically on the elbows, knees, or scalp. An estimated 7.5 million people in the United States will develop the disease, most of them between the ages of 15 and 30. Many people with psoriasis experience pain, discomfort, and self-esteem problems that can interfere with their work and social life.
Although the exact cause of psoriasis is unknown, researchers say the disease is largely genetic—it’s caused by a combination of genes that send the immune system into overdrive, triggering the rapid growth of skin cells that form patches and lesions.
Psoriasis vs. eczema
A dermatologist can likely tell the difference between psoriasis and eczema, but to the untrained eye, these skin conditions can appear similar. Generally speaking, psoriasis appears as thick, red patches that have a scaly buildup on top, according to the American Academy of Dermatology (AAD). These lesions are usually well defined, whereas eczema tends to cause a rash and be accompanied by an intense itch.
In addition, psoriasis tends to occur on the outside of the knees and elbows, and on the lower back and scalp; eczema usually covers the elbow and knee creases and the neck or face.
Research published in 2015 in the Journal of Clinical Medicine suggested that infants and children with psoriasis may be particularly likely to be misdiagnosed with eczema because they may have less scaling than adults.
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Types of psoriasis
Psoriasis can range in severity, from mild patches to severe lesions that can affect more than 5% of the skin. There are five types of the disease: plaque psoriasis, pustular psoriasis, guttate psoriasis, inverse psoriasis, and erythrodermic psoriasis. Some people will have one form, whereas others will have two or more.
Plaque psoriasis appears as red patches with silvery white “scales,” or buildup of dead skin cells, called plaques. It’s the most common type of psoriasis, affecting up to 90% of all people with the disease, according to the AAD. Most often found on the scalp, elbows, lower back, and knees, the plaques themselves will be raised and have clear edges; they may also itch, crack, or bleed.
Pustular psoriasis is a form of psoriasis in which white pustules (or bumps filled with white pus) appear on the skin. In a typical cycle, the skin will turn red, break out in pustules, and then develop scales. There are three types of pustular psoriasis: von Zumbusch pustular psoriasis (which appears abruptly and can be accompanied with fever, chills, and dehydration), palmoplantar pustulosis (which appears on the soles of the feet and the hands), and acropustulosis (a rare form of psoriasis that forms on the ends of the fingers or toes).
Guttate psoriasis is a type of psoriasis that appears as red, scaly teardrop-shaped spots. (The word guttate is Latin for “drop.”) During a flare-up, hundreds of lesions can form on the arms, legs, and torso, although they can also appear on the face, ears, and scalp. Guttate is the second most common type of psoriasis, occurring in about 10% of all people with the disease. It’s most likely to appear in people who are younger than 30, oftentimes after they develop an infection like strep throat.
Inverse psoriasis is a type of psoriasis that appears as smooth, bright red lesions in the armpit, groin, and other areas with folds of skin. Because these regions of the body are prone to sweating and rubbing, inverse psoriasis can be particularly irritating and hard to treat.
Erythrodermic psoriasis is rare but can require immediate treatment or even hospitalization. The lesions look like large “sheets” rather than small spots, as if the area has been burned, and tend to be severely itchy and painful. A flare-up can trigger swelling, infection, and increased heart rate.
Is psoriasis contagious?
Psoriasis is not contagious—it’s a genetic, autoimmune disease. Psoriasis lesions cannot infect other people; likewise, people can’t catch psoriasis from someone else, whether through touching, sexual contact, or swimming in the same pool. It’s unclear, however, whether a majority of the general public is aware of this fact. In a small 2015 survey in the Journal of the American Academy of Dermatology, about 60% of people said they thought that psoriasis was infectious, while 41% said they thought the lesions looked contagious.
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What causes psoriasis?
The simplest answer to the question of what causes psoriasis: your genetics. An estimated 10% of people inherit at least one of the genes that can cause psoriasis. (There are as many as 25 genetic mutations that make someone more likely to develop psoriasis.) But only 2% to 3% of people will develop the disease, according to the National Psoriasis Foundation (NSF). Therefore, researchers believe that psoriasis is caused by a certain combination of genes that spring into action after being exposed to a trigger. Common triggers include stress, an infection (like strep throat), and certain medications (like lithium). Cold, dry weather and sunburns may also trigger psoriasis flares.
When someone with psoriasis is exposed to a trigger, their immune system scrambles to defend itself by producing T cells, a type of white blood cell that helps ward off infections and other diseases. With psoriasis, however, T cell-production goes into overdrive, eventually causing inflammation and faster-than-usual growth of skin cells, leading to psoriasis symptoms.
The signs and symptoms of psoriasis vary depending on the type and severity of the skin disease. Some people may have one form of psoriasis, while others can have two or more.
Raised reddish patches. People with plaque psoriasis can experience a flare-up of red, raised patches. These patches can be itchy or painful or crack and bleed.
Scaly patches. Often seen in plaque psoriasis, scales are patches of built-up dead skin cells that have a silvery-white sheen. They often appear on top of raised, red patches that can be itchy or painful or crack and bleed. People with plaque psoriasis can experience a flare-up of symptoms on their scalp, knees, elbows, and lower back.
White pustules. A characteristic of pustular psoriasis, these white pus-filled blisters can cluster on the hands and feet or spread to most of the body. After the pustules appear, scaling usually follows. In people with von Zumbusch psoriasis, the pustules will dry after 24 to 48 hours, leaving the skin with a “glazed” appearance. In people with palmoplantar pustulosis, the pustules will turn brown, then peel, then start to crust.
Red, smooth lesions. Seen in inverse psoriasis, these very red lesions are smooth and shiny and are found in parts of the body with folds of skin, like the armpits, groin, and under the breasts. Because these lesions tend to be located in sensitive areas, they are prone to irritation from rubbing or sweating.
Red spots. A telltale sign of guttate psoriasis, these small, red spots are shaped like drops and usually appear on the torso, arms, and legs. In most cases, they aren’t as thick as plaque psoriasis lesions, but they can be widespread, numbering into the hundreds.
Nail changes. About 50% of people with psoriasis experience changes to their finger or toenails, including pitting (the appearance of holes in the nail), thickening, and discoloration, according to the NPF.
Areas of the body normally affected by psoriasis
- Hands, feet, nails
- Elbows, knees
- Lower back
- Skin folds
How is psoriasis diagnosed?
There are no special diagnostic tests for psoriasis. Instead, a psoriasis diagnosis is made by a dermatologist, who will examine the skin lesions visually. In some cases, psoriasis can resemble other types of skin conditions, like eczema, so doctors may want to confirm the results with a biopsy. That involves removing some of the skin and looking at the sample under a microscope, where psoriasis tends to appear “thicker” than eczema.
Doctors may also take a detailed record of your family’s medical history: About one-third of people with psoriasis have a first-degree relative who also has the condition. Health care providers may also try to pinpoint psoriasis triggers by asking whether their patients have been under stress lately or are taking a new medication.
There’s no one-size-fits-all psoriasis treatment, and the medications that work for some people may not work for others. The goal, however, is the same for everyone: to find psoriasis medications that can reduce or eliminate psoriasis symptoms. Here are some of the most commonly prescribed therapies.
Topical medications. A first-line form of therapy for mild to moderate conditions, topicals (in psoriasis cream, gel, and ointment forms) are applied directly to the skin in the hopes of reducing inflammation and slowing down skin cell growth. Some are available over-the-counter, like products with salicylic acid and coal tar as active ingredients, while others, like calcipotriene (a form of vitamin D3) and tazarotene (a vitamin A derivative known as a retinoid) are available by prescription. There are also special psoriasis shampoos that can help clear up scalp psoriasis; many contain coal tar and salicylic acid.
Phototherapy. Also called light therapy, phototherapy exposes a person’s skin to ultraviolet light, which is thought to kill the immune cells contributing to psoriasis. Phototherapy can be administered in the form of UVB rays, a combination of UVA and UVB, or UVA rays alongside an oral or topical medication called psoralen (a treatment called PUVA). The catch: These treatments have to be done in a doctor’s office, a psoriasis clinic, or with a specialized phototherapy unit and usually require several visits, which can become expensive. Because indoor tanning increases the risk of skin cancer (especially melanoma), it’s not considered a safe substitute for phototherapy under medical supervision.
Systemic medications. If topical medications and phototherapy don’t work, doctors may recommend taking systemics, or prescription drugs that affect the entire body. These meds can be taken orally or via an injection, and include cyclosporine (which suppresses immune system activity and slows skin cell growth), acitretin (an oral retinoid, or form of vitamin A, that slows down the speed at which skin cells grow and shed), and methotrexate (a medication that was originally used as a cancer treatment, but can also slow down the growth of skin cells).
Biologic drugs. Biologics contain human or animal proteins and can block certain immune cells that are involved in psoriasis. They’re usually recommended for people with moderate to severe psoriasis and are administered via an injection or IV infusion. There are currently three types of biologics that can help treat psoriasis, all of which block immune system chemical messengers that promote inflammation called cytokines. The three types of biologics block the cytokines tumor necrosis factor alpha (TNF-alpha), interleukin 12, interleukin 23, and interleukin 17-A (IL-12, IL-23, and IL-17A, respectively).
Alternative and complementary therapies. Some alternative therapies—including acupuncture, massage, and Reiki—might help relieve certain psoriasis symptoms, like pain. They may also help control stress, a common psoriasis trigger. Other stress-relievers include meditation, mindfulness, exercise, yoga, and Tai Chi. Always talk to your doctor before beginning any alternative psoriasis treatments.
Can psoriasis be cured?
There is currently no cure for psoriasis. As a chronic autoimmune disease, most people with psoriasis will always have it. But it is possible to treat the condition. In fact, the right medications and therapies can reduce symptoms and even clear up the skin entirely in some people.
More psoriasis treatments may be available in the future. Researchers are currently trying to uncover what causes the lesions on a cellular level and how to prevent flare-ups caused by the immune system.
Living with psoriasis
For the millions of Americans who have psoriasis, the skin condition can pose many challenges. Not only can the pain and itching interfere with their ability to sleep or work, but research shows that many people with psoriasis feel unattractive; worse, if they feel self-conscious, they may withdraw from their friends and family and become isolated.
People with psoriasis are also twice as likely to be depressed as those who don’t have the skin condition, according to the NPF, and they can also be more likely to have suicidal thoughts. If you’re feeling a loss of energy, lack of interest in once-enjoyable activities, or an inability to focus, talk to your doctor about whether you may have depression or should see a mental health specialist.
An estimated 30% of people with psoriasis will also develop psoriatic arthritis, a disease which causes joint pain, stiffness, and swelling. Having psoriasis may also make people more likely to develop cardiovascular disease, obesity, and diabetes, according to the NPF.
There are many ways that people living with psoriasis can manage the condition. This includes avoiding tobacco, alcohol, and unhealthy foods. Although there is no “psoriasis diet,” per se, eating healthy meals may help you feel better. You should also keep tabs on whether your joints feel stiff or sore or whether your nails are pitting or turning yellow—two possible signs of psoriatic arthritis. Recognizing these symptoms–and getting treatment–can help prevent further damage to the joints.
Celebrities with psoriasis
Anyone can develop psoriasis—even the most beautiful people on the planet. And as people who are paid to look flawless, many celebrities with psoriasis say that the skin condition delivers a serious blow to their self-esteem and fear that it can interfere with their careers.
In 2011, Kim Kardashian revealed her psoriasis diagnosis on an episode of Keeping Up With the Kardashians. Although her mother, Kris Jenner, was diagnosed with psoriasis at the age of 30, Kim was surprised to learn that she had the skin condition too. “My career is doing ad campaigns and swimsuit photo shoots,” she said in the episode. “People don’t understand the pressure on me to look perfect. Imagine what the tabloids would do to me if they saw all these spots.”
Model and actress Cara Delevingne also has psoriasis, which she struggled to manage while runway modeling. She told London’s The Times in an interview that people would paint her body with foundation to cover up the patches. “It was every single show,” she said. “People would put on gloves and not want to touch me.”
Other models also struggle with psoriasis, like CariDee English, who won America’s Next Top Model in 2006. Partly in response to the hurtful tabloid headlines that called out the lesions on her legs, she posted before-and-after photos of one of her flare-ups, saying, “I knew I didn’t want anyone capturing my psoriasis in a way that wasn’t empowering.”
Other celebs who have psoriasis include golfer Phil Michelson, country singer LeAnn Rimes, and pop star Cyndi Lauper.
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Steven Feldman, MD, PhD, is a professor of pathology and dermatology at Wake Forest University Baptist Medical Center in Winston-Salem, N.C.
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