Psoriasis is a skin disease that causes itchy or sore patches of thick, red skin with silvery scales. It may occur with a form of arthritis. Medications can control the symptoms of psoriasis.

Psoriasis Overview

Reviewed: May 22, 2014

Psoriasis is an autoimmune disease that causes raised, red, scaly patches to appear on the skin.

It typically affects the outside of the elbows, knees, or scalp, though it can appear on any location. Psoriasis is associated with other serious health conditions, such as diabetes, heart disease, and depression. Some people who have psoriasis also get a form of arthritis called psoriatic arthritis.

Several types of psoriasis exist. These include:

plaque psoriasis

nail psoriasis

scalp psoriasis

guttate psoriasis, which primarily affects young adults and children and is characterized by small, water-drop-shaped sores on the trunk, arms, legs and scalp

inverse psoriasis, which mainly affects the skin in the armpits, in the groin, under the breasts, and around the genitals

pustular psoriasis, which is an uncommon form of psoriasis that is characterized by pus-filled blisters

erythrodermic psoriasis, which is the least common type of psoriasis and is characterized by a red, peeling rash that can itch or burn intensely

In psoriasis, the life cycle of skin cells changes. Psoriasis causes cells to build up rapidly on the surface of the skin. The extra skin cells form the thick, silvery scales and itchy, dry, red patches that are sometimes painful.

Men and women develop psoriasis at equal rates. Psoriasis also occurs in all racial groups, but at varying rates. About 1.9% of African-Americans have psoriasis, compared to 3.6% of Caucasians.

Psoriasis often develops between the ages of 15 and 35, but it can develop at any age. About 10% to 15% of those with psoriasis get it before age 10. Some infants have psoriasis, although this is considered rare.

Psoriasis is a persistent, long-lasting (chronic) disease. There may be times when psoriasis symptoms get better and other times when the psoriasis symptoms worsens. Psoriasis can be hard to diagnose because it can look like other skin diseases.

There is no cure for psoriasis, but creams, medications, and light therapy may offer significant symptom relief.

Psoriasis Symptoms

Psoriasis signs and symptoms can vary from person to person but may include one or more of the following:

  • red patches of skin covered with silvery scales
  • small scaling spots (commonly seen in children)
  • dry, cracked skin that may bleed
  • 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.

Most types of psoriasis go through cycles, flaring for a few weeks or months, then subsiding for a time or even going into complete remission. Things that make the symptoms worse include:

  • infections
  • stress
  • dry skin
  • certain medicines

Psoriasis Causes

The cause of psoriasis is not fully understood, but the immune system and genetics play major roles in its development. Usually, something triggers psoriasis to flare. The skin cells in people with psoriasis grow at an abnormally fast rate, which causes the buildup of psoriasis lesions.

Psoriasis is not contagious and psoriasis lesions are not infectious.

Anyone can develop psoriasis, but several factors can increase your risk of developing the disease including:

  • family history
  • viral and bacterial infections such as HIV and recurrent strep throat
  • stress
  • obesity
  • smoking

Psoriasis Diagnosis

Psoriasis can be hard to diagnose because it can look like other skin diseases.

There are no special blood tests or tools to diagnose psoriasis. A dermatologist (a doctor who specializes in skin diseases) or other health care provider usually examines the affected skin and determines if it is psoriasis.

Your doctor may take a piece of the affected skin (a biopsy) and examine it under the microscope. When biopsied, psoriasis skin looks thicker and inflamed compared to skin with eczema or other disease.

Living With Psoriasis

Self-care measures may help improve the appearance and feel of skin damaged by psoriasis.

  • Take daily baths. Bathing daily helps remove scales and calm inflamed skin. Add bath oil, colloidal oatmeal, Epsom salts, or Dead Sea salts to the water and soak. Avoid hot water and harsh soaps, which can worsen symptoms; use lukewarm water and mild soaps that have added oils and fats.
  • Use moisturizer. Blot your skin after bathing, then immediately apply a heavy, ointment-based moisturizer while your skin is still moist. For very dry skin, oils may offer better relief; they stay on longer than creams or lotions do and are more effective at preventing water from evaporating from your skin. During cold, dry weather, you may need to apply a moisturizer several times a day.
  • Expose your skin to small amounts of sunlight. A controlled amount of sunlight can significantly improve lesions, but too much sun can trigger or worsen outbreaks and increase the risk of skin cancer. Before beginning any sunbathing program, ask your doctor about the best way to use natural sunlight to treat your skin. Keep a record of when and how long you are in the sun to help avoid overexposure. Protect healthy, unaffected skin with a broad-spectrum sunscreen with an SPF of at least 30. Apply sunscreen generously, and reapply every two hours or more often if you are swimming or perspiring.
  • Avoid psoriasis triggers, if possible. Find out what triggers, if any, worsen 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.
  • Reduce stress. Stress is a common trigger for a psoriasis flare. At the same time, a psoriasis flare can cause stress.
  • Accept help. It can be difficult talking to friends and family about your psoriasis and how it affects your life. Psoriasis may impact your relationships, but it doesn't need to control them. Find supportive family and friends that will help you manage your symptoms.

Psoriasis Treatments

The goals of psoriasis treatment are to stop the skin cells from growing so quickly, which reduces inflammation and plaque formation, and remove scales and smooth the skin.

Effective treatment of psoriasis can be challenging. The disease is unpredictable, going through cycles of improvement and worsening, and the side effects of psoriasis treatments can also be unpredictable.

Psoriasis treatments can be divided into three main types: topical treatments, light therapy, and systemic medications.

The treatment you and your doctors choose will be based on the type and severity of psoriasis and the areas of skin affected. In general, the traditional approach to therapy is to start with the mildest treatments — topical creams and ultraviolet light therapy (phototherapy) — and then progress to stronger ones only if necessary.

Topical treatments

Creams and ointments applied to the affected skin can effectively treat mild to moderate psoriasis. When the disease is more severe, creams are likely to be combined with oral medications or light therapy. Topical psoriasis treatments include:

  • Topical corticosteroids. These powerful anti-inflammatory drugs are the most frequently prescribed medications for treating mild to moderate psoriasis. They slow cell turnover by suppressing the immune system, which reduces inflammation and relieves associated itching.
  • Vitamin D analogues. These synthetic forms of vitamin D slow down the growth of skin cells. Calcipotriene (Dovonex) is a prescription cream or solution containing a vitamin D analogue that may be used alone to treat mild to moderate psoriasis or in combination with other topical medications or phototherapy. This treatment can irritate the skin. Calcitriol (Rocaltrol) is expensive but may be equally effective and possibly less irritating than calcipotriene.
  • Anthralin. This medication is believed to normalize DNA activity in skin cells. Anthralin (Dritho-Scalp) also can remove scale, making the skin smoother. However, anthralin can irritate skin, and it stains virtually anything it touches, including skin, clothing, countertops and bedding. For that reason, doctors often recommend short-contact treatment — allowing the cream to stay on your skin for a brief time before washing it off.
  • Topical retinoids. Retinoids are commonly used to treat acne and sun-damaged skin, but tazarotene (Tazorac, Avage) was developed specifically for the treatment of psoriasis. Like other vitamin A derivatives, it normalizes DNA activity in skin cells and may decrease inflammation. The most common side effect is skin irritation. It may also increase sensitivity to sunlight, so sunscreen should be applied while using the medication.
  • Calcineurin inhibitors. Currently, calcineurin inhibitors such as tacrolimus (Prograf) and pimecrolimus (Elidel) are approved only for the treatment of atopic dermatitis, but studies have shown them to be effective at times in the treatment of psoriasis. Calcineurin inhibitors are thought to disrupt the activation of T cells, which, in turn, reduces inflammation and plaque buildup.
  • Salicylic acid. Available over-the-counter (nonprescription) and by prescription, salicylic acid promotes sloughing of dead skin cells and reduces scaling. Sometimes it is combined with other medications, such as topical corticosteroids or coal tar, to increase its effectiveness. Salicylic acid is available in medicated shampoos and scalp solutions to treat scalp psoriasis.
  • Coal tar. A thick, black byproduct of the manufacture of petroleum products and coal, coal tar is probably the oldest treatment for psoriasis. It reduces scaling, itching and inflammation. Its mechanism in psoriasis is not exactly known. Coal tar is available in over-the-counter shampoos, creams and oils and in higher concentrations by prescription.
  • Moisturizers. By themselves, moisturizing creams will not heal psoriasis, but they can reduce itching and scaling and can help combat the dryness that results from other therapies. Moisturizers in an ointment base are usually more effective than are lighter creams and lotions.

Light therapy (phototherapy)

This psoriasis treatment uses natural or artificial ultraviolet light. The simplest and easiest form of phototherapy involves exposing your skin to controlled amounts of natural sunlight. Other forms of light therapy include the use of artificial ultraviolet A (UVA) or ultraviolet B (UVB) light either alone or in combination with medications.

Oral or injected medications

If you have severe psoriasis or it is resistant to other treatments, your doctor may prescribe oral or injected drugs. Because of severe side effects, some of these medications are used for only brief periods and may be alternated with other forms of treatment.

  • Retinoids. Related to vitamin A, this group of drugs may reduce the production of skin cells if you have severe psoriasis that does not respond to topical or light-based therapies. Retinoids such as acitretin (Soriatane) can cause severe birth defects and women must avoid pregnancy for at least three years after taking the medication.
  • Methotrexate. Taken orally, methotrexate helps psoriasis by decreasing the production of skin cells and suppressing inflammation. It may also slow the progression of psoriatic arthritis in some people.
  • Cyclosporine. Cyclosporine suppresses the immune system and is similar to methotrexate in effectiveness. Like other immunosuppressant drugs, cyclosporine increases your risk of infection and other health problems, including cancer. Cyclosporine also makes you more susceptible to kidney problems and high blood pressure.
  • Drugs that alter the immune system (biologics). Several biologic agents are approved for the treatment of moderate to severe psoriasis. They include etanercept (Enbrel), infliximab (Remicade), adalimumab (Humira), and ustekinumab (Stelara). These drugs are given by intravenous infusion, intramuscular injection, or subcutaneous injection and are usually used for people who have failed to respond to traditional therapy or who have associated psoriatic arthritis. Biologics work by blocking interactions between certain immune system cells and particular inflammatory pathways. They are derived from natural sources rather than chemical ones, but they must be used with caution because they have strong effects on the immune system and may permit life-threatening infections.
  • Other medications. Thioguanine and hydroxyurea (Droxia, Hydrea) are medications that can be used when other drugs cannot be given for psoriasis.