Updated on April 1, 2020. Medical content reviewed by Dr. Joseph Rosado, MD, M.B.A, Chief Medical Officer
Psoriasis is a chronic and reoccurring condition that varies in severity from minor, localized patches of skin to the eventual complete coverage of the body. Fingernails and toenails are frequently affected by this condition and can be seen as an isolated sign. Psoriasis can also cause inflammation of the joints, which leads to the diagnosis of psoriatic arthritis. Statistically, between 10 and 30 percent of all people with psoriasis also have psoriatic arthritis.
In the U.S., about 7.5 million people have some form of psoriasis. Although the condition can occur at any age, it is more common in adults than in children. The majority of people with psoriasis, about 80 percent, have a very mild form of it. Only about 5 percent of patients with psoriasis have the most severe form. Although there is no cure for the condition, treatment is available to help patients manage their symptoms.
Psoriasis is an ancient condition. In fact, recent research suggests that the ancient Egyptians had come up with a cream that they thought could treat the condition. Researchers found a bottle of lotion that they believe belonged to Queen Hatshepsut, who died of bone cancer in 1458 BCE.
As it turns out, it might have been the cream she was using to ease psoriasis that killed her. Analysis of the ingredients in the lotion revealed that it contained a carcinogen, similar to the tar used in cigarettes. The cream also contained nutmeg and palm oil, two ingredients that would help ease the itch and discomfort of psoriasis.
Ancient people found other ways to try to treat the condition. For example, the first use of phototherapy, or light, to treat psoriasis can be traced back to 1400 BCE.
Hippocrates, the “father of modern medicine” and the creator of the Hippocratic Oath, gave the condition its name, “psora,” from the Greek word meaning “to itch,” around 300 BCE. Hippocrates also developed creams, containing tar, to treat the condition. He would further prescribe arsenic, which is a poison, to patients with the condition.
Other ancient references to psoriasis exist, but might not be describing the condition recognized as psoriasis today. For example, the physician Galen described a disease that he called psoriasis, but that many doctors today believe to have been eczema. Up until the 1900s, it was pretty standard for doctors to put psoriasis, a non-contagious disease, in the same class or category as diseases such as leprosy, which is highly contagious.
Early treatments for the condition ranged from the downright deadly, like arsenic, to the just plain weird, like viper broth or wolf dung. Doctors continued to use arsenic to treat psoriasis and other skin conditions through the middle of the 20th century.
At the beginning of the 1800s, Dr. Robert Willan described and recognized psoriasis as a distinct skin condition, creating a clinical category for it. Unfortunately, the name he chose for it was “lepra vulgaris.” The “lepra” in the name caused many to continue to associate the disease with leprosy.
By the middle of the 1800s, another doctor, Ferdinand von Hebra, changed the disorder’s name, taking out the “lepra” and ending any misconceived connections to leprosy.
Throughout the next century, doctors continued to develop and discover potential treatments for psoriasis. An early discovery was the use of Goa powder, which comes from a tree native to Brazil. Goa powder had been used to treat fungal infections on the skin. A doctor’s misdiagnosis of psoriasis as a fungal infection led to the discovery that the powder could effectively treat psoriasis.
By the time of World War I, doctors were able to create a synthetic form of Goa powder for use as treatment. They were also beginning to explore treatment methods including X-rays, UV radiation and coal tar.
In 1950, doctors discovered hydrocortisone, a type of corticosteroid. A few years later, they realized that hydrocortisone could help patients manage symptoms of psoriasis. Around the same time, some other medications, such as methotrexate and fumaric acid, also became available as treatment options.
In the 1970s, the discovery that psoriasis was some type of autoimmune disorder, and that some patients had distinct genetic markers for it, led to the development of biologic medicines to treat the condition. Biologic medications came on the market in the 1990s and are still commonly prescribed to treat psoriasis.
Although doctors still don’t know the particular cause of psoriasis, the immune system has a role to play in the condition. Essentially, T cells, which usually protect the body from invaders like viruses and bacteria, instead end up attacking healthy skin cells.
At the same time, the T cells trigger the development of new skin cells, as well as new neutrophils and other white blood cells. Those cells end up on the surface of the skin, creating the scaling and redness associated with psoriasis.
The presence of an excessive amount of new skin cells interferes with the body’s ability to shed those cells. As a result, plaques, or areas of thick, scaly skin, form.
Although the immune system plays a significant role in the development of psoriasis, it’s not the only potential cause of the condition. A person’s genes can also play a role in determining whether he or she develops psoriasis.
About one-third of people with the condition have a family member who also has psoriasis. Although the genes associated with the skin disease can occur in up to 10 percent of the population, only about 3 percent of people with the genes usually end up developing symptoms.
Several factors can also trigger psoriasis in people who are prone to the condition. In some instances, knowing what triggers an outbreak can help you manage to avoid symptoms. Common triggers include:
Although the symptoms of psoriasis can be slightly different from patient to patient, some symptoms are relatively common. They include:
Some people might have only mild symptoms of the condition, or their symptoms might be limited to one relatively small area of the body. People with more severe forms of the disease can have symptoms all over their skin. It’s also common for symptoms to come and go in cycles.
If you have psoriasis, you might have a flare-up of symptoms that lasts for a week or a few months. Once the symptoms clear up, you might not have another outbreak for some time. It’s also possible to have a single outbreak or flare-up of the condition just once in your life, then never experience it again.
Medical professionals often divide psoriasis into five major types. The kind of psoriasis you have influences the type of symptoms you develop or the way the disease looks on your skin.
1. Plaque Psoriasis
The most common type of psoriasis, plaque psoriasis usually causes the red, scaly patches associated with the disease. The patches are often very itchy and can become cracked, which leads to bleeding. About 80 percent of people with the condition have this form of it. The plaques most commonly develop on the knees, elbows, scalp and lower back.
Although most cases of psoriasis occur in adults, guttate often develops in children. It’s the second most common type of the disease and occurs in about 10 percent of patients. The condition’s primary symptom is lesions that look like little red dots on the skin. One common trigger for guttate psoriasis is strep throat.
Pustular psoriasis causes a person to develop white blisters on the skin. The skin around the blisters is usually red. Although the condition looks infectious, the blisters are full of non-contagious, non-infectious pus made up of white blood cells. Usually, the pustules form on the hands and feet, but can develop anywhere on the body.
Inverse psoriasis causes areas of shiny redness to develop in the folds of the skin. The red areas can form in the armpits, groin area or under the breasts. Often, people with the inverse type of psoriasis have another type of psoriasis at the same time.
One of the rarest and most life-threatening forms of psoriasis, erythrodermic psoriasis causes red patches to form all over the body. The condition causes lots of pain and itchiness. One hallmark of this type of psoriasis is that it causes the plaques to be shed from the skin in sheets. If you have an outbreak of what looks to be erythrodermic psoriasis, it’s important to see a doctor right away.
Psoriasis is often associated with or occasionally occurs along with several other conditions. For example, if you have psoriasis, you are also more likely to develop another type of autoimmune disease, such as Crohn’s disease. Inflammatory bowel disease and Crohn’s disease occur up to 7.5 times more often in people with psoriasis than in the general population.
A person with psoriasis might also have an increased chance of developing the following:
Another condition, known as psoriasis arthritis, also occasionally develops in people with psoriasis. Along with attacking the skin cells, the immune system also attacks the joints when a person has psoriasis arthritis. That causes inflammation and swelling.
One of the most common signs of psoriasis arthritis is the development of swollen toes and fingers. Many patients have swelling in their fingers and toes before they have any joint issues. Other symptoms include pain in the feet and lower back.
What living with psoriasis is like depends on the severity of your symptoms. For some patients, flare-ups are very rare and don’t interfere with their lives. The flare-ups might only cause mild symptoms or can be easily covered up with clothing.
In more severe cases, psoriasis can have a significant adverse effect on a person’s overall quality of life. The condition is often linked to depression, which can occur in as much as half the population with psoriasis.
Misconceptions and misunderstanding about psoriasis can often make it difficult for patients with the condition to develop relationships. Although the condition isn’t contagious, people do occasionally make assumptions when they see the plaques on another person’s skin. It can also be difficult for a person with psoriasis to explain his or her condition to a new partner or friend.
Although having psoriasis can present a number of challenges, many people with the condition can live happy lives and form long-lasting and loving relationships with others.
Although treatment options for psoriasis have come a long way since viper broth and arsenic, they still leave a lot to be desired regarding effectiveness and side effects. The most popular treatments for the condition are topical corticosteroids, such as hydrocortisone. The creams help minimize inflammation and itching, and are often prescribed for mild to moderate cases.
The major drawback of corticosteroids is that long-term use causes the skin to thin. The medicine can also become less effective over time and might even stop working. For that reason, doctors usually recommend that patients use the creams or ointments on a short-term basis only.
Vitamin D, or creams containing a Vitamin D analogue, are another treatment option. The Vitamin D helps slow down the production of excess skin cells. The downside is that the available ointments are usually very irritating to the skin or very expensive.
Anthralin is another topical cream that can help treat signs of psoriasis. The medicine works in two ways: It slows down the production of skin cells while helping remove or clear up existing plaques. The big problem with it is that it’s very irritating and will stain fabrics and other surfaces it comes into contact with.
A class of medicines known as biologics also often help to treat psoriasis. These medications work by suppressing an overactive immune system so it can’t attack otherwise healthy skin cells. The big drawback is that they also keep the immune system from protecting the body against real threats, like viruses and bacteria. If you are taking an immunosuppressant drug, your doctor will want to regularly screen you to make sure you haven’t picked up a potentially deadly infection.
Medical marijuana can be a great treatment option for patients who suffer from psoriasis. Topical steroid creams, which are prescribed to many patients, can have horrifying side effects — such as the possibility of developing tuberculosis or lymphoma. Medical cannabis is ideal for any irritations or inflammation of the skin, as it is very therapeutic and beneficial as an anti-inflammatory. CB2 receptors in a patient’s epidermis have been proven to react very well to cannabinoids and leave skin feeling healthy and more improved.
Smoking tobacco cigarettes isn’t recommended for patients with psoriasis, as the smoke can trigger a flare-up. By the same token, it’s not recommended that psoriasis patients smoke marijuana to get any benefits from it. Studies have suggested that the best way for a person with psoriasis to benefit from cannabis is to apply cannabinoid oil directly to the skin.
It’s thought that cannabis can help people with psoriasis manage their symptoms in three ways. First, cannabis might be able to slow down the production of skin cells. A 2007 study published in the Journal of Dermatological Science examined the effectiveness of a variety of cannabinoids in slowing down the proliferation of skin cells during a flare-up. The researchers concluded that cannabinoids could play a significant role in the treatment of psoriasis.
The second way that cannabis can help people with psoriasis is by minimizing the pain and discomfort felt during a flare-up. There have been several studies that examined the role marijuana can play in reducing pain. Finally, the third way that marijuana can help people with psoriasis is by suppressing the immune system. The study from the Journal of Dermatological Science also examined cannabis’ ability to reduce the production of T cells, which are the immune response that triggers the excess production of skin cells.
The one drawback of using cannabis for psoriasis treatment is that psoriasis isn’t currently listed as a qualifying illness in many of the states that allow medical marijuana treatment. Some states could allow a patient to use medical marijuana for psoriasis, as long as the psoriasis is severely affecting a person’s quality of life. California, for example, has a special rider on its law that allows a doctor to prescribe cannabis for conditions not included on the state’s list. Colorado and Massachusetts are two more states with similar rules.
If you suffer from psoriasis, you don’t have to live with the discomfort or embarrassment. Search for a medical marijuana doctor or dispensary in your state and learn more about how cannabis can help ease symptoms of psoriasis.