Topic Overview

What is psoriasis?

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.

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.

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.

What causes psoriasis?

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.

What are the symptoms?

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 color, 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).

How is psoriasis diagnosed?

A doctor can usually
diagnose psoriasis by looking at the patches on your skin, scalp, or nails.
Special tests aren’t usually needed.

How is it treated?

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

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.

What can you do at home for psoriasis?

Skin care
at home can help control psoriasis. Follow these tips to care for

  • Use creams or lotions, baths, or soaks to
    keep your skin moist.
  • Try short exposure to sunlight or
    ultraviolet (UV) light.
  • Follow instructions for
    skin products and prescribed medicines. It may take a period of trial and error
    until you know which skin products or methods work best for you. For mild
    symptoms of psoriasis, some
    over-the-counter medicines, such as aloe vera, may be

It’s also important to avoid those things that can cause
psoriasis symptoms to flare up or make the condition worse. Things to avoid

  • Skin injury. An injury
    to the skin can cause psoriasis patches to form anywhere on the body, including
    the site of the injury. This includes injuries to your nails or nearby skin
    while trimming your nails.
  • Stress and anxiety. Stress can cause psoriasis to appear suddenly (flare) or can
    make symptoms worse.
  • Infection. Infections
    such as
    strep throat can cause psoriasis to appear suddenly,
    especially in children.
  • Certain medicines.
    Some medicines, such as nonsteroidal anti-inflammatory drugs (NSAIDs),
    beta-blockers, and lithium, have been found to make
    psoriasis symptoms worse. Talk with your doctor. You may be able to take a
    different medicine.
  • Overexposure to sunlight. Short periods of sun exposure reduce psoriasis in
    most people, but too much sun can damage the skin and cause skin cancer. And
    sunburns can trigger flares of psoriasis.
  • Alcohol. Alcohol use can cause symptoms to flare
  • Smoking. Smoking can
    make psoriasis worse. If you smoke, try to quit.

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.

Frequently Asked Questions

Learning about psoriasis:

Being diagnosed:

Getting treatment:

Ongoing concerns:

Living with psoriasis:

Health Tools

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:

  • Raised, bright red patches of skin, often covered with loose, silvery scales, usually on the knees, elbows, or low back.
  • Tiny areas of bleeding when skin scales are
    picked or scraped off (Auspitz’s sign).
  • Mild scaling to thick,
    crusted plaques on the scalp.
  • Itching, especially during sudden
    flare-ups or when the psoriasis patches are in body folds, such as under the
    breasts or buttocks.
  • Discolored or pitted nails.

Other symptoms of psoriasis may include:

  • Similar plaques in the same area on both sides
    of the body (for example, both knees or both elbows).
  • Flare-ups of
    many raindrop-shaped patches (guttate psoriasis).
  • Joint swelling, tenderness, and pain (psoriatic arthritis).
  • Psoriasis patches that appear after an injury, such as a cut, a burn, or too much sun. This is called Koebner’s phenomenon. Because this response is common, it’s important for people with psoriasis to avoid irritating or injuring their skin.

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

What Happens

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:

  • Cold.
  • Dry climates.
  • Stress.
  • Infection.
  • Skin injury.
  • Certain medicines.

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.

Mild, moderate, and severe psoriasis

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.


  • Plaques cover a
    small portion of the body, such as the elbows or knees.


  • Plaques cover several large areas. For example,
    most of the scalp may be affected.
  • Any joint pain is mild, but not
  • Plaques tend to be visible to other


  • Psoriasis on the
  • Plaques that cover at least 10% of your body.
  • Pustular psoriasis with large, fluid-filled plaque and
    severe scaling.
  • Erythrodermic psoriasis with severe inflammation and
    shedding (sloughing) of the skin.
  • Psoriatic arthritis,
    which includes ongoing joint swelling, tenderness, limitation of range of
    motion, or joint warmth or redness. Severe cases can result in joint

Learn more about the different types of psoriasis.

What Increases Your Risk

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 1

Other factors that can contribute to the
development of psoriasis include:

  • Emotional or physical stress. Stress may cause psoriasis to
    appear suddenly or make symptoms worse (although this has not been proved in
  • Infection. Infections such as
    strep throat can cause psoriasis to appear suddenly,
    especially in children.
  • Skin injuries. An injury to the skin can
    cause psoriasis patches to form anywhere on the body, including the site of the
    injury. This includes injuries to your nails or nearby skin while trimming your
  • Smoking.
    Smoking may make you more likely to get psoriasis and make the symptoms more
    severe.footnote 3

When To Call a Doctor

Call your doctor if you have:

  • Symptoms of
    psoriasis. Early treatment may help keep the
    condition from getting worse. For more information, see Symptoms.
  • Signs of developing bacterial infection. These include:
    • Increased pain, swelling, redness,
      tenderness, or heat.
    • Red streaks extending from the
    • A discharge of pus.
    • Fever of
      100.4°F (38°C) or higher with
      no other cause.

If you are currently being treated for psoriasis, call your
doctor if you:

  • Have severe and widespread psoriasis and your
    skin is more irritated or inflamed than usual, especially if you have another
  • Are taking medicine for psoriasis and have serious side
    effects, such as vomiting, bloody diarrhea, chills, or a fever.

Who to see

Health professionals who can
diagnose and treat psoriasis include:

To prepare for your appointment, see the topic Making the Most of Your Appointment.

Exams and Tests

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:

  • Biopsy. If it is hard to diagnose the condition by looking at your skin, your doctor may remove a small skin sample and send it to a lab for analysis.
  • X-rays. If you have joint pain, X-rays may be taken to look for psoriatic arthritis.
  • Blood test. It can help rule out
    other forms of arthritis.
  • Throat culture. If your doctor thinks you may have guttate psoriasis, he or she may want to check for strep throat.
  • KOH test. Sometimes this skin test is done to rule out a fungal infection.

Treatment Overview

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:

  • Creams, ointments, and lotions to moisturize
    the skin.
  • Shampoos, oils, and sprays to treat psoriasis of the
  • Some exposure to sunlight.

Depending on what type of psoriasis you have, treatment may also include:

  • Skin products that your doctor prescribes.
  • Pills that your doctor prescribes.
  • Shots to help your immune system.
  • Phototherapy, which involves exposing your skin to special ultraviolet light.

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

Avoid triggers

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.

Treat scalp or nail 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 or corticosteroid solutions.

Ask for help

Psoriasis can cause a lot of stress and
affect how you feel about yourself. Seek information or counseling 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 National Psoriasis
Foundation at


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.

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:

  • Take care of your skin, scalp, and nails. For mild symptoms of psoriasis, various over-the-counter products,
    such as aloe vera, may be soothing and keep your skin moist.

  • Try some of the many psoriasis creams, ointments, and shampoos that you can buy without a prescription. For more information, see Medications.
  • Follow your schedule for
    sunlight or ultraviolet light treatments.
  • Be aware of possible medicine reactions. Certain medicines can trigger psoriasis or make
    symptoms worse.
  • Limit alcohol to no more
    than 2 drinks a day for men or 1 drink a day for women. Alcohol use can cause symptoms to flare up.
  • Studies haven’t found any “psoriasis diet” that can cure
    or improve the condition, despite claims over the years. Try to eat a balanced diet and stay at a healthy weight.

What to avoid

Avoid these triggers:

  • Cold, dry climates. Cold weather may make symptoms worse. Hot, humid weather
    and sunlight may improve symptoms. (But hot, humid weather may make certain
    types of psoriasis worse.)
  • Scratching and picking skin. And avoid skin injuries (cuts or scrapes). An injury to the skin can cause
    psoriasis patches to form anywhere on the body, including the site of the
    injury. This includes injuries to your nails or nearby skin while trimming your
  • Stress and anxiety. Stress may cause psoriasis to
    appear suddenly (flare). Or it can make symptoms worse, although this has not been
    proved in studies.
  • Infection. Infections such as
    strep throat can cause one type of psoriasis (called
    guttate psoriasis) to appear suddenly, especially in
  • Smoking. Smoking can make your symptoms worse. If you smoke, consider quitting.

Stress and psoriasis

Stress can make your symptoms worse. Some things that can help reduce stress include:

  • Practicing relaxation with breathing exercises, yoga, or meditation.
  • Getting active. Regular exercise may help you feel better mentally and physically.
  • Finding support. To locate a support group in your area, contact the National Psoriasis Foundation online at
  • Learning more about psoriasis. This can help you with your treatment and help you explain your condition to others.


Medicines you put on your skin (topical medicines)

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.

  • For mild psoriasis,
    you may be able to control psoriasis using an over-the-counter medicine, including corticosteroid creams. Be safe with medicines. Read and follow all instructions on the label.
  • For moderate to severe psoriasis,
    you may need to use a topical medicine prescribed by your doctor, such as a
    stronger corticosteroid or a medicine related to vitamin D called calcipotriene. Other
    topical medicines include anthralin and tars.

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.

Pills or shots

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. A person who takes biologics has a slightly higher risk of getting a serious infection.

Medicine choices

Over-the-counter topical medicines

There are many types of nonprescription products, including corticosteroid creams, for psoriasis. Examples of their active ingredients include:

  • Salicylic acid, found in products such as Psoriasin Body Wash and Dermasolve e70.
  • Coal tar, found in products such as Elta Tar and Neutrogena T/Gel.

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

  • Corticosteroids, which are the most
    common treatment for psoriasis. Betamethasone is an
    example of a topical corticosteroid.
  • Calcipotriene. This
    is a form of vitamin D.
  • Retinoids, which are medicines related
    to vitamin A. An example is tazarotene.
  • Calcineurin inhibitors, such as pimecrolimus or tacrolimus.
  • Anthralin and
    tars. The use of anthralin and tars has decreased
    recently, replaced by other medicines such as calcipotriene and

Topical medicines used with ultraviolet (UV) light

  • Psoralen and UVA light (called
  • Tars and UVB light (called
    Goeckerman treatment)
  • Anthralin and UVB light (called the Ingram


  • Retinoids
  • Cyclosporine
  • Methotrexate


Biologics used to treat psoriasis or psoriatic arthritis include infliximab (Remicade), secukinumab (Cosentyx), and ustekinumab (Stelara).

What to think about

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 isn’t 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.

Other Treatment


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

Complementary medicine treatments

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. For more information, see the website of the
National Psoriasis Foundation at

Other Places To Get Help


National Psoriasis Foundation (U.S.)

American Academy of Dermatology



  1. Abel EA, Lebwohl M (2012). Psoriasis. In EG Nabel et al., eds., Scientific American Medicine, chap. 48. Hamilton, ON: BC Decker. Accessed November 21, 2016.
  2. Puchalsky D (2011). Papulosquamous eruptions-Psoriasis. In ET Bope et al., eds., Conn’s Current Therapy 2011, pp. 823-827. Philadelphia: Saunders.
  3. Fortes C, et al. (2005). Relationship between smoking and the clinical severity of psoriasis. Archives of Dermatology, 141: 1580-1584.

Other Works Consulted

  • Aloe (2010). In A DerMarderosian, J Beutler, eds., Review of Natural Products. St. Louis: Wolters Kluwer Health.
  • Giezen TJ, et al. (2008). Safety-related regulatory actions for biologicals approved in the United States and the European Union. Journal of the American Medical Association, 300(16): 1887-1896.
  • Kimball AB, et al. (2008). National Psoriasis Foundation clinical consensus on psoriasis comorbidities and recommendations for screening. Journal of the American Academy of Dermatology, 58(6): 1031-1042.
  • Lebwohl MG, Kerkhof P (2010). Psoriasis. In MG Lebwohl et al., eds., Treatment of Skin Disease: Comprehensive Therapeutic Strategies, 3rd ed., pp. 626-636. Edinburgh: Saunders Elsevier.
  • Nestle FO, et al. (2009). Psoriasis. New England Journal of Medicine, 361(5): 496-509.
  • Schmitt J, et al. (2008). Efficacy and tolerability of biologic and nonbiologic systemic treatments for moderate-to-severe psoriasis: Meta-analysis of randomized controlled trials. British Journal of Dermatology, 159(3): 513-526.


ByHealthwise Staff
Primary Medical Reviewer Adam Husney, MD – 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
Specialist Medical Reviewer Amy McMichael, MD – Dermatology

Current as ofOctober 5, 2017