Psoriasis is a skin disease that causes red, itchy scaly patches, most commonly on the knees, elbows, trunk and scalp.

Psoriasis is a common, long-term (chronic) disease with no cure. It tends to go through cycles, flaring for a few weeks or months, then subsiding for a while or going into remission. Treatments are available to help you manage symptoms. And you can incorporate lifestyle habits and coping strategies to help you live better with psoriasis.

Psoriasis signs and symptoms can vary from person to person. Common signs and symptoms include:

• Red patches of skin covered with thick, silvery scales
• Small scaling spots (commonly seen in children)
• Dry, cracked skin that may bleed or itch
• Itching, burning or soreness
• Thickened, pitted or ridged nails
• Swollen and stiff joints

Psoriasis patches can range from a few spots of dandruff-like scaling to major eruptions that cover large areas. The most commonly affected areas are the lower back, elbows, knees, legs, soles of the feet, scalp, face and palms.

Most types of psoriasis go through cycles, flaring for a few weeks or months, then subsiding for a time or even going into remission.

There are several types of psoriasis, including:

• Plaque psoriasis. The most common form, plaque psoriasis causes dry, raised, red skin patches (lesions) covered with silvery scales. The plaques might be itchy or tender, and there may be few or many. They usually appear on elbows, knees, lower back and scalp.
• Nail psoriasis. Psoriasis can affect fingernails and toenails, causing pitting, abnormal nail growth and discoloration. Psoriatic nails might loosen and separate from the nail bed (onycholysis). Severe cases may cause the nail to crumble.
• Guttate psoriasis. This type primarily affects young adults and children. It's usually triggered by a bacterial infection such as strep throat. It's marked by small, drop-shaped, scaling lesions on the trunk, arms or legs.
• Inverse psoriasis. This mainly affects the skin folds of the groin, buttocks and breasts. Inverse psoriasis causes smooth patches of red skin that worsen with friction and sweating. Fungal infections may trigger this type of psoriasis.
• Pustular psoriasis. This rare form of psoriasis causes clearly defined pus-filled lesions that occur in widespread patches (generalized pustular psoriasis) or in smaller areas on the palms of the hands or the soles of the feet.
• Erythrodermic psoriasis. The least common type of psoriasis, erythrodermic psoriasis can cover your entire body with a red, peeling rash that can itch or burn intensely.
• Psoriatic arthritis. Psoriatic arthritis causes swollen, painful joints that are typical of arthritis. Sometimes the joint symptoms are the first or only symptom or sign of psoriasis. And at times only nail changes are seen. Symptoms range from mild to severe, and psoriatic arthritis can affect any joint. It can cause stiffness and progressive joint damage that in the most serious cases may lead to permanent joint damage.

When to see a doctor

If you suspect that you may have psoriasis, see your doctor. Also, talk to your doctor if your psoriasis:

• Becomes severe or widespread
• Causes you discomfort and pain
• Causes you concern about the appearance of your skin
• Leads to joint problems, such as pain, swelling or inability to perform daily tasks
• Doesn't improve with treatment

Psoriasis is thought to be an immune system problem that causes the skin to regenerate at faster than normal rates. In the most common type of psoriasis, known as plaque psoriasis, this rapid turnover of cells results in scales and red patches.

Just what causes the immune system to malfunction isn't entirely clear. Researchers believe both genetics and environmental factors play a role. The condition is not contagious.

Psoriasis triggers

Many people who are predisposed to psoriasis may be free of symptoms for years until the disease is triggered by some environmental factor. Common psoriasis triggers include:

• Infections, such as strep throat or skin infections
• Weather, especially cold, dry conditions
• Injury to the skin, such as a cut or scrape, a bug bite, or a severe sunburn
• Stress
• Smoking and exposure to secondhand smoke
• Heavy alcohol consumption
• Certain medications — including lithium, high blood pressure medications and antimalarial drugs
• Rapid withdrawal of oral or systemic corticosteroids

Anyone can develop psoriasis. About a third of instances begin in the pediatric years. These factors can increase your risk:

• Family history. The condition runs in families. Having one parent with psoriasis increases your risk of getting the disease, and having two parents with psoriasis increases your risk even more.
• Stress. Because stress can impact your immune system, high stress levels may increase your risk of psoriasis.
• Smoking. Smoking tobacco not only increases your risk of psoriasis but also may increase the severity of the disease. Smoking may also play a role in the initial development of the disease.

If you have psoriasis, you're at greater risk of developing other conditions, including:

• Psoriatic arthritis, which causes pain, stiffness and swelling in and around the joints
• Eye conditions, such as conjunctivitis, blepharitis and uveitis
• Obesity
• Type 2 diabetes
• High blood pressure
• Cardiovascular disease
• Other autoimmune diseases, such as celiac disease, sclerosis and the inflammatory bowel disease called Crohn's disease
• Mental health conditions, such as low self-esteem and depression

Your doctor will ask questions about your health and examine your skin, scalp and nails. Your doctor might take a small sample of skin (biopsy) for examination under a microscope. This helps determine the type of psoriasis and rule out other disorders.

Psoriasis treatments aim to stop skin cells from growing so quickly and to remove scales. Options include creams and ointments (topical therapy), light therapy (phototherapy), and oral or injected medication.

Which treatments you use depends on how severe the psoriasis is and how responsive it has been to previous treatment. You might need to try different drugs or a combination of treatments before you find an approach that works for you. Usually, however, the disease returns.

Topical therapy

• Corticosteroids. These drugs are the most frequently prescribed medications for treating mild to moderate psoriasis. They are available as ointments, creams, lotions, gels, foams, sprays and shampoos. Mild corticosteroid ointments (hydrocortisone) are usually recommended for sensitive areas, such as your face or skin folds, and for treating widespread patches. Topical corticosteroids might be applied once a day during flares, and on alternate days or weekends only to maintain remission.

  Your doctor may prescribe a stronger corticosteroid cream or ointment— triamcinolone (Acetonide, Trianex), clobetasol (Temovate) for smaller, less-sensitive or tougher-to-treat areas.

  Long-term use or overuse of strong corticosteroids can thin the skin. Over time, topical corticosteroids may stop working.

• Vitamin D analogues. Synthetic forms of vitamin D, such as calcipotriene and calcitriol (Vectical) slow skin cell growth. This type of drug may be used alone or with topical corticosteroids. Calcitriol may cause less irritation in sensitive areas. Calcipotriene and calcitriol are usually more expensive than topical corticosteroids.

• Retinoids. Tazarotene (Tazorac, Avage) is available as a gel and cream and applied once or twice daily. The most common side effects are skin irritation and increased sensitivity to light.

  Tazarotene isn't recommended when you're pregnant or breast-feeding or if you intend to become pregnant.

• Calcineurin inhibitors. Calcineurin inhibitors — such as tacrolimus (Protopic) and pimecrolimus (Elidel) — reduce inflammation and plaque buildup. They can be especially helpful in areas of thin skin, such as around the eyes, where steroid creams or retinoids are too irritating or may cause harmful effects.

  Calcineurin inhibitors are not recommended when you're pregnant or breast-feeding or if you intend to become pregnant. This drug is also not intended for long-term use because of a potential increased risk of skin cancer and lymphoma.

• Salicylic acid. Salicylic acid shampoos and scalp solutions reduce the scaling of scalp psoriasis. It may be used alone, or to enhance the ability of other medications to more easily penetrate the skin.

• Coal tar. Coal tar reduces scaling, itching and inflammation. It's available over-the-counter or by prescription in various forms, such as shampoo, cream and oil. These products can irritate the skin. They're also messy, stain clothing and bedding, and can have a strong odor.

  Coal tar treatment isn't recommended for women who are pregnant or breast-feeding.

• Goeckerman therapy. Some doctors combine coal tar treatment with light therapy, which is known as Goeckerman therapy. The two therapies together are more effective than either alone because coal tar makes skin more receptive to UVB light.
• Anthralin. Anthralin (another tar product) is a cream used to slow skin cell growth. It can also remove scales and make skin smoother. It should not be used on the face or genitals. Anthralin can irritate skin, and it stains almost anything it touches. It's usually applied for a short time and then washed off.

Light therapy

Light therapy is a first-line treatment for moderate to severe psoriasis, either alone or in combination with medications. It involves exposing the skin to controlled amounts of natural or artificial light. Repeated treatments are necessary. Talk with your doctor about whether home phototherapy is an option for you.

• Sunlight. Brief, daily exposures to sunlight (heliotherapy) might improve psoriasis. Before beginning a sunlight regimen, ask your doctor about the safest way to use natural light for psoriasis treatment.
• UVB broadband. Controlled doses of UVB broadband light from an artificial light source can treat single patches, widespread psoriasis and psoriasis that doesn't improve with topical treatments. Short-term side effects might include redness, itching and dry skin. Moisturizing regularly can help ease your discomfort.
• UVB narrowband. UVB narrowband light therapy might be more effective than UVB broadband treatment and in many places has replaced broadband therapy. It's usually administered two or three times a week until the skin improves and then less frequently for maintenance therapy. Narrowband UVB phototherapy may cause more-severe and longer lasting burns, however.

• Psoralen plus ultraviolet A (PUVA). This treatment involves taking a light-sensitizing medication (psoralen) before exposure to UVA light. UVA light penetrates deeper into the skin than does UVB light, and psoralen makes the skin more responsive to UVA exposure.

  This more aggressive treatment consistently improves skin and is often used for more-severe cases of psoriasis. Short-term side effects include nausea, headache, burning and itching. Long-term side effects include dry and wrinkled skin, freckles, increased sun sensitivity, and increased risk of skin cancer, including melanoma.

• Excimer laser. With this form of light therapy, a strong UVB light targets only the affected skin. Excimer laser therapy requires fewer sessions than does traditional phototherapy because more powerful UVB light is used. Side effects can include redness and blistering.

Oral or injected medications

If you have moderate to severe psoriasis or other treatments haven't worked, your doctor may prescribe oral or injected (systemic) drugs. Because of the potential for severe side effects, some of these medications are used for only brief periods and might be alternated with other treatments.

• Steroids. If you have a few small, persistent psoriasis patches, your doctor might suggest an injection of triamcinolone right into the lesions.
• Retinoids. Acitretin (Soriatane) and other retinoids are pills used to reduce the production of skin cells. Side effects might include dry skin and muscle soreness. These drugs are not recommended when you're pregnant or breast-feeding or if you intend to become pregnant.

• Methotrexate. Usually administered weekly as a single oral dose, methotrexate (Trexall) decreases the production of skin cells and suppresses inflammation. It's less effective than adalimumab (Humira) and infliximab (Remicade). It might cause upset stomach, loss of appetite and fatigue. People taking methotrexate long term need ongoing testing to monitor their blood counts and liver function.

  Men and women should stop taking methotrexate at least three months before attempting to conceive. This drug is not recommended when you're breast-feeding.

• Cyclosporine. Taken orally for severe psoriasis, cyclosporine (Neoral) suppresses the immune system. It's similar to methotrexate in effectiveness but cannot be used continuously for more than a year. Like other immunosuppressant drugs, cyclosporine increases your risk of infection and other health problems, including cancer. People taking cyclosporine need ongoing monitoring of their blood pressure and kidney function.

  These drugs are not recommended when you're pregnant, breast-feeding or if you intend to become pregnant.

• Biologics. These drugs, usually administered by injection, alter the immune system in a way that disrupts the disease cycle and improves symptoms and signs of disease within weeks. Several of these drugs are approved for the treatment of moderate to severe psoriasis in people who haven't responded to first-line therapies. The therapeutic options are rapidly expanding. Examples include etanercept (Enbrel), infliximab (Remicade), adalimumab (Humira), ustekinumab (Stelara), secukinumab (Cosentyx) and ixekizumab (Taltz). These types of drugs are expensive and may or may not be covered by health insurance plans.

  Biologics must be used with caution because they carry the risk of suppressing your immune system in ways that increase your risk of serious infections. In particular, people taking these treatments must be screened for tuberculosis.

• Other medications. Thioguanine (Tabloid) and hydroxyurea (Droxia, Hydrea) are medications that can be used when other drugs can't be given. Apremilast (Otezla) is taken by mouth twice a day. It's especially effective at reducing itching. Talk with your doctor about possible side effects of these drugs.

Treatment considerations

Although doctors choose treatments based on the type and severity of psoriasis and the areas of skin affected, the traditional approach is to start with the mildest treatments — topical creams and ultraviolet light therapy (phototherapy) — in people with typical skin lesions (plaques) and then progress to stronger ones only if necessary. People with pustular or erythrodermic psoriasis or associated arthritis usually need systemic therapy from the beginning of treatment. The goal is to find the most effective way to slow cell turnover with the fewest possible side effects.

Alternative medicine

A number of alternative therapies claim to ease the symptoms of psoriasis, including special diets, creams, dietary supplements and herbs. None have definitively been proved effective. But some alternative therapies are deemed generally safe and might reduce itching and scaling in people with mild to moderate psoriasis. Other alternative therapies are useful in avoiding triggers, such as stress.

• Aloe extract cream. Taken from the leaves of the aloe vera plant, aloe extract cream may reduce redness, scaling, itching and inflammation. You might need to use the cream several times a day for a month or more to see any improvement in your skin.
• Fish oil supplements. Oral fish oil therapy used in combination with UVB therapy might reduce the amount of affected skin. Applying fish oil to the affected skin and covering it with a dressing for six hours a day for four weeks might improve scaling.
• Oregon grape. Also known as barberry, this product is applied to the skin and may reduce the severity of psoriasis.
• Essential oils. Essential oils used for aromatherapy have been shown to reduce stress and anxiety.

If you're considering dietary supplements or other alternative therapy to ease the symptoms of psoriasis, consult your doctor. He or she can help you weigh the pros and cons of specific alternative therapies.

Try these self-care measures to better manage your psoriasis and feel your best:

• Take daily baths. Bathing daily helps remove scales and calm inflamed skin. Add bath oil, colloidal oatmeal and Epsom salts to the water and soak for at least 15 minutes. Use lukewarm water and mild soaps that have added oils and fats.
• Use moisturizer. After bathing, gently pat dry and apply a heavy, ointment-based moisturizer while your skin is still moist. For very dry skin, oils may be preferable — they have more staying power than creams or lotions do. If moisturizing seems to improve your skin, apply it one to three times daily.
• Cover the affected areas overnight. Before going to bed, apply an ointment-based moisturizer to the affected skin and wrap with plastic wrap. When you wake, remove the plastic and wash away scales.
• Expose your skin to small amounts of sunlight. Ask your doctor about the best way to use natural sunlight to treat your skin. A controlled amount of sunlight can improve psoriasis, but too much sun can trigger or worsen outbreaks and increase the risk of skin cancer. Log your time in the sun, and protect skin that isn't affected by psoriasis with sunscreen with a sun protection factor (SPF) of at least 30.
• Apply medicated cream or ointment. Apply an over-the-counter cream or ointment containing hydrocortisone or salicylic acid to reduce itching and scaling. If you have scalp psoriasis, try a medicated shampoo that contains coal tar.
• Avoid psoriasis triggers. Notice what triggers your psoriasis, and take steps to prevent or avoid them. Infections, injuries to your skin, stress, smoking and intense sun exposure can all worsen psoriasis.
• Avoid drinking alcohol. Alcohol consumption may decrease the effectiveness of some psoriasis treatments. If you have psoriasis, avoid alcohol. If you do drink, use moderation.
• Strive to maintain a healthy lifestyle. In addition to quitting smoking and drinking moderately, if at all, you can manage your psoriasis by being active, eating well and maintaining a healthy weight.

Coping with psoriasis can be a challenge, especially if the affected skin covers a large area of your body or is visible to other people. The ongoing, persistent nature of the disease and the treatment challenges only add to the burden.

Here are some ways to help you cope and to feel more in control:

• Get educated. Find out as much as you can about the disease, and research your treatment options. Understand possible triggers of the disease so that you can better prevent flare-ups. Educate those around you — including family and friends — so that they can recognize, acknowledge and support your efforts in dealing with the disease.
• Follow your doctor's recommendations. If your doctor recommends certain treatments and lifestyle changes, be sure to follow them. Ask questions if anything is unclear.
• Find a support group. Consider joining a support group with other members who have the disease. Some people find comfort in sharing their struggles and meeting people who face similar challenges. Ask your doctor for information on psoriasis support groups in your area or online.
• Use cover-ups when you feel it necessary. On those days when you feel particularly self-conscious, cover the psoriasis with clothing or use cosmetic cover-up products, such as body makeup or a concealer. These products can mask redness and psoriasis plaques. They can irritate the skin, however, and shouldn't be used on open sores, cuts or unhealed lesions.

You'll likely first see your family doctor or a general practitioner. In some cases, you may be referred directly to a specialist in skin diseases (dermatologist).

Here's some information to help you prepare for your appointment and to know what to expect from your doctor.

What you can do

Make a list of the following:

• Symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment
• All medications, vitamins and herbs you take, including doses
• Questions to ask your doctor

For psoriasis, some basic questions you might ask your doctor include:

• What might be causing my signs and symptoms?
• Do I need diagnostic tests?
• What treatments are available, and which do you recommend for me?
• What types of side effects can I expect?
• Will the treatment you recommended cause a remission in my symptoms?
• How quickly can I expect results?
• What are the alternatives to the primary approach you're suggesting?
• I have other medical conditions. How can I manage these conditions together?
• What skin care routines and products do you recommend to improve my symptoms?

What to expect from your doctor

Your doctor is likely to ask you several questions, such as:

• When did you begin having symptoms?
• How often do you have these symptoms?
• Have your symptoms been continuous or occasional?
• Does anything seem to improve your symptoms?
• What, if anything, appears to worsen your symptoms?