Patient education: Psoriasis (Beyond the Basics)

PSORIASIS OVERVIEW — 

Psoriasis is a chronic skin disorder that causes areas of thickened, inflamed, red skin, often covered with silvery scales. Children and adolescents can develop psoriasis, but it occurs primarily in adults. Psoriasis is not an infection, and it is not contagious.

The severity of psoriasis is determined by how much of the body's surface is covered and how much it affects a person's quality of life. Psoriasis is not curable, although many treatments are available to reduce the symptoms and appearance of the disease.

PSORIASIS CAUSES — 

Researchers have not identified the exact cause of psoriasis. However, the disease develops due to a combination of immune, genetic, and environmental factors.

Immune system — The immune system plays an important role in the skin changes that occur in psoriasis. Understanding the normal process of skin development is helpful for understanding why skin changes occur in people with psoriasis.

The skin is made up of several layers (figure 1). The top layer is the epidermis, a layer of cells that divide and eventually die, covering the surface of the skin with a layer of dead cells called the stratum corneum. The middle layer is the dermis; this is the layer where collagen and blood vessels are found. The inner layer is the subcutaneous layer, a layer of fat underneath the skin. Every day, as cells in the epidermis die and become part of the stratum corneum, dead cells at the top of the stratum corneum also are shed. This balance prevents the dead skin layer from becoming too thick.

In skin affected by psoriasis, immune cells enter the skin through blood vessels and cause the epidermis to grow very rapidly and to stop shedding properly (figure 2). This causes thickening of the skin as well as the scaly build-up composed of dead skin cells that is seen on areas affected by psoriasis. Dilated blood vessels in the dermis that feed the rapidly growing epidermis cause the red color of the skin.

Genetics — Genetic factors play a role in determining whether someone develops psoriasis. About 40 percent of people with psoriasis or psoriatic arthritis (a type of arthritis closely related to psoriasis) have family members with the disorder (see "Patient education: Psoriatic arthritis (Beyond the Basics)"). Several genes have been identified that make people more susceptible to psoriasis, but there is no genetic test that can definitely tell whether an individual will develop the disease.

Environment and behavior — Certain environmental and behavioral factors seem to be linked to psoriasis. Bacterial and viral infections, alcohol consumption, and certain medications (including beta blockers, lithium, and antimalarial drugs) may affect a person's risk of developing psoriasis or worsen symptoms. Smoking appears to increase the risk and severity of psoriasis, particularly for psoriasis of the palms and soles.

PSORIASIS SYMPTOMS — 

Symptoms of psoriasis include:

●Areas of skin that are dry or red, usually covered with silvery-white scales, and sometimes with raised edges

●Rashes on the scalp, genitals, or in the skin folds

●Itching and skin pain

●Joint pain, swelling, or stiffness

●Nail abnormalities, such as pitted, discolored, or crumbly nails

TYPES OF PSORIASIS — 

There are several common types of psoriasis.

Plaque psoriasis — Plaque psoriasis is the most common form of psoriasis. Plaque psoriasis tends to affect young and middle aged adults, but can occur at any age. The individual skin plaques are usually between 0.4 and 4 inches (1 to 10 cm) wide but may be larger. Some of the most common areas for plaques are the scalp, elbows, knees, and back (picture 1 and picture 2 and picture 3). The severity of plaque psoriasis varies widely. Plaque psoriasis may occur in just a few small areas or may cover a large portion of the body.

Guttate psoriasis — This type of psoriasis is sometimes linked to a recent streptococcal infection, usually pharyngitis (eg, strep throat). It often affects children or young adults with no past history of psoriasis, and causes a sudden eruption of small scaly papules on the trunk of the body (picture 4).

Pustular psoriasis — Pustular psoriasis can be a severe, and occasionally life-threatening, form of psoriasis. It develops quickly, with multiple small pustules that may join into larger areas (picture 5). Symptoms can include fever and abnormal blood levels of white blood cells and calcium. Pustular psoriasis can also cause pus-filled blisters on the palms of the hands and soles of the feet. These blisters can crack, causing painful breaks in the skin, and can be disabling.

Inverse psoriasis — This type of psoriasis affects less visible body areas, such as the groin, armpits, buttocks, genitals, and the area under the breasts (picture 6). Sometimes this is mistakenly diagnosed as a fungal or bacterial infection.

Nail psoriasis — Some people with psoriasis develop nail problems, including tiny pits over the surface of the nails. The pits look as if someone has taken a pin and pricked the nail several times (picture 7). In addition, nails may develop a tan-brown color (also known as "oil spots") or may separate from the nail bed (also known as "onycholysis") (picture 8 and picture 9). In more severe cases, people have thick, crumbling nails.

Treatment of nail psoriasis is difficult and may include injections of steroids into the nail bed or internal medications, such as methotrexate or other immunomodulatory drugs. (See 'Psoriasis treatment' below.)

Psoriatic arthritis — Up to one-third of people with psoriasis also have psoriatic arthritis, a condition that causes joint pain and swelling. Skin signs usually develop first, although about 15 percent of psoriasis patients who develop arthritis (joint swelling and stiffness) do so before other symptoms of psoriasis. People with psoriatic arthritis often have severe nail problems. (See "Patient education: Psoriatic arthritis (Beyond the Basics)".)

Other associated conditions — Not everyone with psoriasis gets depressed, but there is a higher than normal frequency of depression in people with psoriasis. Psoriasis also has been associated with obesity and an increased risk of heart disease.

PSORIASIS DISEASE COURSE — 

Psoriasis is usually a lifelong condition and is not currently curable, although the severity of the disease can improve or worsen over time and can be controlled with treatment.

In people with certain forms of the disease, itching or pain and stiffness is severe and disabling. Some people with visible psoriasis lesions have feelings of embarrassment about their appearance. Stress, anxiety, loneliness, and low self-esteem can occur as a result.

People with psoriasis have higher rates of depression compared with those without the condition. People who have depression often benefit from working with a psychologist, clinical social worker, or other therapist to discuss their illness and identify possible ways to cope. A number of organizations, such as the National Psoriasis Foundation (www.psoriasis.org), are available to provide educational and psychosocial support to people with psoriasis and their families. (See 'Where to get more information' below.)

PSORIASIS DIAGNOSIS — 

Psoriasis can be diagnosed by examining the skin. Occasionally, a skin biopsy or scraping may be taken to rule out other disorders. There is no blood test that can definitively diagnose psoriasis.

PSORIASIS TREATMENT — 

Psoriasis is not curable, but many treatments are available that can reduce the bothersome symptoms and appearance of the disease. Treatment depends upon the severity of the disease, the cost and convenience of the treatment, and a person's response to the treatment. A combination of therapies is often recommended.

Referral to a dermatologist (a doctor who specializes in skin conditions) may be needed if the diagnosis of psoriasis is uncertain, if the initial treatment does not improve symptoms, or if the disease is widespread or severe. People with psoriatic arthritis may need to see a rheumatologist (a doctor who specializes in joint conditions).

Medicines applied to the skin — Many medications are available that can be rubbed onto the skin to treat psoriasis. Because psoriasis cannot be cured, continued use of medication is required to maintain improvement. For the best results, patients must use treatments as directed.

Emollients — Keeping skin soft and moist can minimize itching and tenderness. Over-the-counter moisturizers such as petroleum jelly or thick creams may be recommended; these should be applied immediately after bathing or showering.

Topical corticosteroids — Corticosteroids (sometimes called "steroids" but distinct from body building steroids) are applied to the skin to help to reduce inflammation. This is often done twice per day at the beginning of treatment. As a patient's psoriasis improves, a doctor may recommend decreasing the frequency of treatment.

These cortisone-type creams and ointments are available in a variety of strengths (potencies); the least potent are available without a prescription (eg, hydrocortisone 1% cream) and are usually only effective in sensitive skin areas like the face and body folds. More potent formulations require a prescription. Many other forms of these medications (for example, gel, lotion, liquid, shampoo foam, and spray) are available. Some people with psoriasis prefer these forms of medication over creams or ointments.

Side effects can include thinning of the skin and stretch marks (particularly when applied to normal skin). These effects are most likely to occur when high-potency topical corticosteroids are used for long periods of time. It is important to use these medications properly to reduce the risk for these side effects. A patient who notices these effects should contact their doctor.

Calcipotriene or calcitriol — Calcipotriene (sample brand names: Dovonex, Sorilux) and calcitriol (sample brand name: Vectical) are related to vitamin D and work by slowing the growth of skin cells in the epidermis. These medicines can be used instead of or in addition to topical corticosteroids. They are usually applied twice a day when used alone. Skin irritation is the most common side effect.

Other preparations (sample brand names: Taclonex, Enstilar) combine calcipotriene with a corticosteroid (betamethasone) in a once-daily treatment.

Tapinarof — Tapinarof cream (brand name: Vtama) may improve psoriasis by reducing inflammation in the skin. It is applied once daily.

Some of the possible side effects include folliculitis (inflammation of hair follicles) and skin irritation.

Topical roflumilast — Roflumilast cream (brand name: Zoryve) reduces inflammation in the skin. Roflumilast cream is applied once per day.

Some possible, but infrequent, side effects include diarrhea, headache, insomnia, and nausea.

Topical calcineurin inhibitors — Topical calcineurin inhibitors, including tacrolimus ointment (brand name: Protopic) and pimecrolimus cream (brand name: Elidel), reduce inflammation in the skin. These medications can be used to treat psoriasis, especially on the face and skin folds, such as in the armpits or under the breasts. Possible side effects include burning, stinging, or itching sensations at the site of application.

Tazarotene — Tazarotene cream or gel (sample brand name: Tazorac) is a skin treatment derived from vitamin A. It is usually applied once per day. Skin irritation is a common side effect.

Tazarotene is also available in a combination with a potent topical corticosteroid (brand name: Duobrii). This is usually applied once daily at bedtime.

Other treatments — Other skin treatments for psoriasis include salicylic acid and tar. These treatments are not as effective as other psoriasis therapies but are sometimes used with topical corticosteroid treatment.

●Salicylic acid – Salicylic acid may help to reduce flakes on skin with psoriasis. It is available without a prescription and in different forms, such as shampoos, body washes, and creams.

●Tar – Tar reduces inflammation in the skin. It is available in the form of shampoos, creams, oils, and lotions without a prescription; these are usually applied to the skin or scalp once or twice per day. Tar products can have an unpleasant odor and can stain skin, hair, and clothing.

Ultraviolet light/phototherapy — Exposure to ultraviolet light, also called "phototherapy," is an effective way to treat some forms of psoriasis. Natural sunlight, which consists of ultraviolet B (UVB) and ultraviolet A (UVA) rays, has been observed to improve psoriasis. Ultraviolet light B, delivered in a dermatologist's office or at home using a home phototherapy machine, is a treatment for psoriasis.

Phototherapy is considered one of the safest treatments for psoriasis that cannot be satisfactorily improved with medications applied to the skin. Some of the short-term risks of phototherapy include sunburn, skin dryness, and itching. Potential long-term risks include premature skin aging and skin cancer. (See "Patient education: Melanoma treatment; localized melanoma (Beyond the Basics)".)

Lasers that deliver UVB can also treat psoriasis. The laser allows higher doses of UVB exposure to be directed only to active psoriasis lesions while sparing normal skin; as a result, the lesions may improve with fewer treatments than with traditional ultraviolet light therapy. UVB laser treatment is most suitable for people who have small areas of psoriasis.

Biologics — Medications called "biologics" target the immune system and can be beneficial for psoriasis. These are given as an injection (shot) under the skin.

The biologics for psoriasis work by targeting proteins called "cytokines." These include "interleukin-17," "interleukin-23," and "tumor necrosis factor-alpha." Examples are listed below.

●Interleukin-17 (IL-17) inhibitors

•Bimekizumab (brand name: Bimzelx)

•Brodalumab (brand name: Siliq)

•Ixekizumab (brand name: Taltz)

•Secukinumab (brand name: Cosentyx)

●Interleukin-23 (IL-23) inhibitors

•Guselkumab (brand name: Tremfya)

•Risankizumab (brand name: Skyrizi)

•Tildrakizumab (brand name: Ilumya)

•Ustekinumab (brand name: Stelara)

●Tumor necrosis factor-alpha (TNF-alpha) inhibitors

•Adalimumab (brand name: Humira)

•Certolizumab pegol (brand name: Cimzia)

•Etanercept (brand name: Enbrel)

•Infliximab (sample brand name: Remicade)

Biologics can be highly effective for the treatment of psoriasis. Biologics are generally prescribed for people with psoriasis that cannot be satisfactorily improved with other treatments.

Biologics can increase a person's risk for infections and might be less safe for people with certain diseases. Before starting a biologic, your health care provider will review your medical history and might order tests to check for certain diseases. Depending on the treatment selected, your clinician might ask about tuberculosis, hepatitis, other infections, inflammatory bowel disease, heart disease, multiple sclerosis, depression, cancer, pregnancy, or other conditions.

Other medications

Apremilast — Apremilast (brand name: Otezla) is an oral medication that can be used to treat psoriasis. It is usually taken twice daily. People with severe kidney problems typically take apremilast only once daily.

The most common side effects of apremilast are diarrhea, nausea, upper respiratory tract infection, and headache. In addition, people taking apremilast should contact their health care provider immediately if they notice the emergence or worsening of depression, suicidal thoughts, or other mood changes while taking this medication. If you are thinking about hurting yourself or someone else, get help right away. In the United States, help is available through the 988 Suicide & Crisis Lifeline. Call or text 988 or go to https://chat.988lifeline.org.

Deucravacitinib — Deucravacitinib (brand name: Sotyktu) is an oral medication that can be used to treat psoriasis. It is taken once daily.

Deucravacitinib may increase the risk of viral infections like shingles, other herpes infections, and folliculitis (inflammation of hair follicles). Some people may also need to be monitored for possible liver problems or high levels of cholesterol and triglycerides (fats) in the blood.

Methotrexate — Methotrexate is used to treat psoriasis. It is usually taken once per week, and it may be taken in oral (pill) form or as an injection.

Methotrexate can affect blood cell counts and liver function in some people. Patients should avoid drinking alcohol while on methotrexate because alcohol also damages the liver.

While taking methotrexate, many providers recommend taking folic acid daily or weekly to reduce the risk of certain methotrexate side effects, such as upset stomach and a sore mouth.

Severe side effects can rarely occur with methotrexate (including damage to the lungs, liver, and bone marrow, and even death), so careful dosing and monitoring is essential. Serious interactions may occur with certain medications, particularly sulfa-type antibiotics. Methotrexate can cause significant harm to an unborn baby and, therefore, is not safe to take during pregnancy.

Retinoids — Retinoids are derived from vitamin A. An oral form called acitretin (brand name: Soriatane) is used for psoriasis.

Some side effects of retinoids include cracking and drying of the lips and skin, nosebleeds, trouble seeing in the dark, hair loss, joint pain, and depression. Acitretin may also cause increased levels of triglycerides and liver enzymes in the blood.

Acitretin can cause severe birth defects and is only slowly removed from the body, so people should not get pregnant while taking acitretin or within three years after stopping the medication. Thus, for practical reasons, this medication is typically not prescribed to people who could get pregnant, and people who are taking acitretin should not donate blood.

Other drugs — Several medications that suppress the immune system can be used to treat severe psoriasis for a short period of time. These include cyclosporine, hydroxyurea, and azathioprine.

Dietary changes — The role of dietary interventions in treating psoriasis has been unclear. Experts recommend that people with psoriasis who are overweight or obese reduce the number of calories they consume to try to lose weight. They also recommend a gluten-free diet for people with psoriasis who have been diagnosed with celiac disease or confirmed to have gluten sensitivity based on blood tests. Beyond this, there is no specific approach that has been proven to improve psoriasis symptoms; however, eating a nutritious, balanced diet (high in fruits, vegetables, and whole grains; and low in unhealthy fats and added sugar) has many other health benefits.

WHERE TO GET MORE INFORMATION — 

Your health care provider is the best source of information for questions and concerns related to your medical problem.

This article will be updated as needed on our website (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for health care professionals, are also available. Some of the most relevant are listed below.

Patient level information — UpToDate offers two types of patient education materials.

The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.

Patient education: Psoriasis (The Basics)
Patient education: Psoriatic arthritis in adults (The Basics)
Patient education: Psoriatic arthritis in children (The Basics)
Patient education: Topical corticosteroid medicines (The Basics)
Patient education: Itchy skin (The Basics)
Patient education: Phototherapy (The Basics)
Patient education: How to use topical medicines (The Basics)

Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.

Patient education: Psoriatic arthritis (Beyond the Basics)
Patient education: Melanoma treatment; localized melanoma (Beyond the Basics)
Patient education: Tuberculosis (Beyond the Basics)

Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.

Approach to the patient with a scalp disorder
Approach to the patient with anal pruritus
Approach to the patient with pustular skin lesions
Clinical manifestations and diagnosis of psoriatic arthritis
Psoriasis: Epidemiology, clinical manifestations, and diagnosis
Management of psoriasis in pregnancy
Pathogenesis of psoriatic arthritis
Chronic plaque psoriasis in adults: Overview of management
Treatment of psoriatic arthritis

The following organizations also provide reliable health information.

●National Library of Medicine

     (https://medlineplus.gov/psoriasis.html)

●National Institute on Arthritis and Musculoskeletal and Skin Diseases

     (https://www.niams.nih.gov/health-topics)

●American Academy of Dermatology

     (https://www.aad.org/public/diseases/psoriasis)

●American Academy of Allergy, Asthma and Immunology

     (https://www.aaaai.org/)

●National Psoriasis Foundation

     1-800-723-9166

     (https://www.psoriasis.org/)

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