Top of the page
Psoriasis (say "suh-RY-uh-sus") is a long-term (chronic) skin problem that causes skin cells to grow too quickly, resulting in thick, white, silvery, or red patches of skin.
Normally, skin cells grow gradually and flake off about every 4 weeks. New skin cells grow to replace the outer layers of the skin as they shed.
But in psoriasis, new skin cells move rapidly to the surface of the skin in days rather than weeks. They build up and form thick patches called plaques (say "plax"). The patches range in size from small to large. They most often appear on the knees, elbows, scalp, hands, feet, or lower back. Psoriasis is most common in adults. But children and teens can get it too.
Having psoriasis can be embarrassing, and many people, especially teens, avoid swimming and other situations where patches can show. But there are many types of treatment that can help keep psoriasis under control.
Experts believe that psoriasis occurs when the immune system overreacts, causing inflammation and flaking of skin. In some cases, psoriasis runs in families.
People with psoriasis often notice times when their skin gets worse. Things that can cause these flare-ups include a cold and dry climate, infections, stress, dry skin, and taking certain medicines.
Psoriasis isn't contagious. It can't be spread by touch from person to person.
Symptoms of psoriasis appear in different ways. Psoriasis can be mild, with small areas of rash. When psoriasis is moderate or severe, the skin gets inflamed with raised red areas topped with loose, silvery, scaling skin. If psoriasis is severe, the skin becomes itchy and tender. And sometimes large patches form and may be uncomfortable. The patches can join together and cover large areas of skin, such as the entire back.
Psoriasis can also affect the fingernails and toenails, causing the nails to pit, change colour, and separate from the nail bed.
In some people, psoriasis causes joints to become swollen, tender, and painful. This is called psoriatic arthritis (say "sor-ee-AT-ik ar-THRY-tus").
Symptoms may disappear (go into remission), even without treatment, and then return (flare up).
A doctor can usually diagnose psoriasis by looking at the patches on your skin, scalp, or nails. Special tests aren't usually needed.
Most cases of psoriasis are mild, and treatment begins with skin care. This includes keeping your skin moist with creams and lotions. These are often used with other treatments including shampoos, ultraviolet light, and medicines your doctor prescribes.
In some cases, psoriasis can be hard to treat. You may need to try different combinations of treatments to find what works for you. Treatment for psoriasis may continue for a lifetime.
Skin care at home can help control psoriasis. Follow these tips to care for psoriasis:
It's also important to avoid those things that can cause psoriasis symptoms to flare up or make the condition worse. Things to avoid include:
Studies have not found that specific diets can cure or improve the condition, even though some advertisements claim to. For some people, not eating certain foods helps their psoriasis. Most doctors recommend that you eat a balanced diet to be healthy and stay at a healthy weight.
Health Tools help you make wise health decisions or take action to improve your health.
The exact cause of psoriasis isn't known.
Doctors believe that the immune system overreacts, causing inflammation and flaking of skin.
Many scientists believe that psoriasis can be inherited. About one-third of people who have psoriasis have one or more family members with the condition.footnote 1 But it isn't clear that genetic factors alone determine whether you get psoriasis.
Psoriasis isn't contagious—it can't be spread by touch from person to person.
There are several types of psoriasis. Symptoms for each type may vary, but the major symptoms are:
Other symptoms of psoriasis may include:
Several other skin conditions have symptoms similar to psoriasis. And some medicine reactions can cause symptoms (such as reddened skin) similar to psoriasis. Talk to your doctor about the medicines you are taking.
Psoriasis is usually a long-term problem. Symptoms tend to come and go in a cycle of flares, when symptoms get worse, and remission, when symptoms improve and go away for awhile. In other cases psoriasis may persist for long periods of time without getting better or worse.
Several things can make symptoms worse, depending on the type of psoriasis. These factors, or triggers, include:
A few cases of psoriasis may go away without treatment. But it's usually best to treat psoriasis so that it doesn't get worse. If it becomes severe and widespread, it may be much harder to treat.
The severity of psoriasis is indicated by the amount of redness and scaling, the thickness of the large areas of raised skin patches (plaques), and the percentage of your skin that is affected.
Learn more about the different types of psoriasis.
Many doctors believe that psoriasis may be passed down from parents to their children (inherited). This is because certain genes are found in families who are affected by psoriasis.footnote 2 About one-third of people who have psoriasis have one or more family members with the condition.footnote 3
Other factors that can contribute to the development of psoriasis include:
Call your doctor if you have:
If you are currently being treated for psoriasis, call your doctor if you:
Your family doctor or general practitioner can diagnose and treat psoriasis. You may be referred to a specialist, such as a:
Your doctor can often recognize psoriasis by looking at your skin, scalp, and nails.
Tests aren't usually needed. But one or more of the following tests may be done:
Currently there is no cure for psoriasis. But many types of treatment are available, including products applied to the skin, phototherapy, and oral medicines, which can help control psoriasis. Most cases are mild and can be treated with skin products. In some cases, psoriasis can be hard to treat if it is severe and widespread. Most psoriasis returns, even mild forms.
The purpose of treatment is to slow the rapid growth of skin cells that causes psoriasis and to reduce inflammation. Treatment is based on the type of psoriasis you have, its location, its severity, and your age and overall health.
Treatment can also depend on how much you are affected by the condition, either physically (because of factors such as joint pain) or emotionally (because of embarrassment or frustration from a skin rash that may cover a large or visible area of the body). For example, you may get more aggressive treatment if your psoriasis is severe or if the patches frequently upset you.
Most cases are mild and can be treated with:
Depending on what type of psoriasis you have, treatment may also include:
You may need to try different treatments before you find one that works well for you. It's important to discuss your treatment and progress with your doctor.
Many doctors will recommend that treatments be changed or rotated after a certain period of time to make treatment more effective and to reduce side effects.
People respond differently to psoriasis treatments. A treatment that worked one time may not work again. A treatment that didn't work the first time may work when tried again later.
For more information, see:
It's also important to avoid anything that can trigger a flare-up of psoriasis or make the condition worse. Stress, skin injury, infection, and use of alcohol can all contribute to symptom flare-ups. Streptococcal infections, which usually affect the upper respiratory tract, are linked to guttate psoriasis.
Scalp and nail psoriasis can be hard to treat. Both conditions are more likely to improve with medicines taken by mouth (oral medicines). Treatment for the scalp often includes tar shampoos and corticosteroid solutions.
Psoriasis can cause a lot of stress and affect how you feel about yourself. Seek information or counselling from your doctor. For tips on dealing with stress, see Home Treatment. You can also get educational materials and find support networks by contacting the Psoriasis Society of Canada at www.psoriasissociety.org.
There is no way to prevent psoriasis. But you can take steps to improve symptoms or help reduce the number of psoriasis flare-ups. For more information, see Home Treatment.
Most of the time psoriasis can be treated at home. These tips may improve your symptoms or help reduce the number of psoriasis flare-ups:
Avoid these triggers:
Stress can make your symptoms worse. Some things that can help reduce stress include:
Treatment using more than one topical medicine is often done. This can help prevent side effects from some of the stronger medicines. For example, you may use one medicine during the week but another on the weekend.
Your doctor may have you use occlusion therapy. This means wrapping the skin after applying moisturizers or medicated creams or gels. The wrap can be fabric or plastic. Occlusion keeps the area moist and can make the medicated creams work better. Steroid cream may be used with the occlusion treatment method for small areas, but not for more than a few days. Occlusion of large areas may cause side effects such as thinning of the skin. Talk to your doctor before using occlusion therapy, to make sure that you do it safely.
Medicines taken by mouth (oral medicines) may be used to treat moderate to severe psoriasis.
Sometimes this type of medicine is given as shots instead of pills.
Medicines called biologics may be used to treat severe psoriasis or psoriasis that hasn't improved after other treatments. Biologics are similar to or the same as proteins made by the body. These medicines block the harmful response of the body's immune system that causes the symptoms of psoriasis.
Some of these medicines are pills and some are given through a needle. Biologics are expensive but work well to treat moderate-to-severe psoriasis. They usually help within a few weeks. People who take biologics have a slightly increased risk of getting serious infections.
Over-the-counter topical medicines.
There are many types of non-prescription products, including corticosteroid creams, for psoriasis. Examples of their active ingredients include:
These products are used to treat small patches of psoriasis and symptoms, including itching, redness, flaking, and scaling of the skin and scalp. For some people, they may eliminate scales and sores caused by psoriasis.
Topical medicines that a doctor prescribes:
Topical medicines used with ultraviolet (UV) light
Biologics used to treat psoriasis or psoriatic arthritis include infliximab (Remicade), secukinumab (Cosentyx), and ustekinumab (Stelara).
Some medicines used to treat psoriasis can cause serious side effects. You and your doctor will discuss how long to use treatments that could cause harm. You will also need to see your doctor regularly and may have blood tests while using some medicines.
Many oral or injected medicines used to treat psoriasis aren't safe during pregnancy. If you are pregnant, talk to your doctor before taking any medicines.
Surgery is not used to treat psoriasis of the skin or scalp. But surgery may be used to treat nails that are severely disfigured or damaged from psoriasis. Surgical removal of a nail may be done in a clinic or doctor's office as an outpatient procedure.
Phototherapy uses ultraviolet light to slow the rapid growth of cells that occurs in psoriasis. This treatment can be effective, but your skin should be checked often by your doctor (at least once or twice a year) for any skin damage or skin cancer.
Complementary therapies are often used by people with skin diseases, including psoriasis.
These treatments include the use of herbs, vitamins, certain diets, and stress reduction. They may relieve psoriasis symptoms in some people.
Some people notice that natural sunlight and seawater help their psoriasis symptoms. People seeking this treatment may go to seaside resorts, some of which have special programs and medical help for people with psoriasis.
CitationsAbel EA, Lebwohl M (2012). Psoriasis. In EG Nabel et al., eds., Scientific American Medicine, chap. 48. Hamilton, ON: BC Decker. https://www.deckerip.com/decker/scientific-american-medicine/chapter/48/pdf. Accessed November 21, 2016.Puchalsky D (2011). Papulosquamous eruptions—Psoriasis. In ET Bope et al., eds., Conn's Current Therapy 2011, pp. 823–827. Philadelphia: Saunders.Abel EA, Lebwohl M (2012). Psoriasis. In EG Nabel et al., eds., Scientific American Medicine, chap. 48. Hamilton, ON: BC Decker. https://www.deckerip.com/decker/scientific-american-medicine/chapter/48/pdf. Accessed November 21, 2016.Fortes C, et al. (2005). Relationship between smoking and the clinical severity of psoriasis. Archives of Dermatology, 141: 1580–1584.
Current as of: July 2, 2020
Author: Healthwise StaffMedical Review: Adam Husney MD - Family MedicineDonald Sproule MDCM, CCFP - Family MedicineE. Gregory Thompson MD - Internal MedicineMartin J. Gabica MD - Family MedicineKathleen Romito MD - Family MedicineElizabeth T. Russo MD - Internal MedicineAmy McMichael MD - Dermatology
Current as of: July 2, 2020
Author: Healthwise Staff
Medical Review:Adam Husney MD - Family Medicine & Donald Sproule MDCM, CCFP - Family Medicine & E. Gregory Thompson MD - Internal Medicine & Martin J. Gabica MD - Family Medicine & Kathleen Romito MD - Family Medicine & Elizabeth T. Russo MD - Internal Medicine & Amy McMichael MD - Dermatology
To learn more about Healthwise, visit Healthwise.org.
© 1995-2021 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.