Overview of Psoriasis
Psoriasis is a chronic (long-lasting) disease in which the immune system becomes overactive, causing skin cells to multiply too quickly. Patches of skin become scaly and inflamed, most often on the scalp, elbows, or knees, but other parts of the body can be affected as well. Scientists do not fully understand what causes psoriasis, but they know that it involves a mix of genetics and environmental factors.
The symptoms of psoriasis can sometimes go through cycles, flaring for a few weeks or months followed by periods when they subside or go into remission. There are many ways to treat psoriasis, and your treatment plan will depend on the type and severity of disease. Most forms of psoriasis are mild or moderate and can be successfully treated with creams or ointments. Managing common triggers, such as stress and skin injuries, can also help keep the symptoms under control.
Having psoriasis carries the risk of getting other serious conditions, including:
- Psoriatic arthritis, a chronic form of arthritis that causes pain, swelling, and stiffness of the joints and places where tendons and ligaments attach to bones (entheses).
- Cardiovascular events, such heart attacks and strokes.
- Mental health problems, such as low self-esteem, anxiety, and depression.
- People with psoriasis may also be more likely to get certain cancers, Crohn’s disease, diabetes, metabolic syndrome, obesity, osteoporosis, uveitis (inflammation of the middle of the eye), liver disease, and kidney disease.
Who Gets Psoriasis?
Anyone can get psoriasis, but it is more common in adults than in children. It affects men and women equally.
Types of Psoriasis
There are different types of psoriasis, including:
- Plaque psoriasis. This is the most common kind, and it appears as raised, red patches of skin that are covered by silvery-white scales. The patches usually develop in a symmetrical pattern on the body and tend to appear on the scalp, trunk, and limbs, especially the elbows and knees.
- Guttate psoriasis. This type usually appears in children or young adults, and looks like small, red dots, typically on the torso or limbs. Outbreaks are often triggered by an upper respiratory tract infection, such as strep throat.
- Pustular psoriasis. In this type, pus-filled bumps called pustules surrounded by red skin appear. It usually affects the hands and feet, but there is a form that covers most of the body. Symptoms can be triggered by medications, infections, stress, or certain chemicals.
- Inverse psoriasis. This form appears as smooth, red patches in folds of skin, such as beneath the breasts or in the groin or armpits. Rubbing and sweating can make it worse.
- Erythrodermic psoriasis. This is a rare but severe form of psoriasis characterized by red, scaly skin over most of the body. It can be triggered by a bad sunburn or taking certain medications, such as corticosteroids. Erythrodermic psoriasis often develops in people who have a different type of psoriasis that is not well controlled, and it can be very serious.
Symptoms of Psoriasis
Symptoms of psoriasis vary from person to person, but some common ones are:
- Patches of thick, red skin with silvery-white scales that itch or burn, typically on the elbows, knees, scalp, trunk, palms, and soles of the feet.
- Dry, cracked skin that itches or bleeds.
- Thick, ridged, pitted nails.
Some patients have a related condition called psoriatic arthritis, which is characterized by stiff, swollen, painful joints. If you have symptoms of psoriatic arthritis, it is important to see your doctor soon because this is one of the most destructive forms of arthritis.
The symptoms of psoriasis tend to come and go. You may find that there are times when your symptoms get worse, called flares, followed by times when you feel better.
Causes of Psoriasis
Psoriasis is an immune-mediated disease, which means that your body’s immune system starts overacting and causing problems. If you have psoriasis, immune cells become active and produce molecules that set off the rapid production of skin cells. This is why skin in people with the disease is inflamed and scaly. Scientists do not fully understand what triggers the faulty immune cell activation, but they know that it involves a combination of genetics and environmental factors. Many people with psoriasis have a family history of the disease, and researchers have pinpointed some of the genes that may contribute to its development. Nearly all of them play a role in the function of the immune system.
Some external factors that may increase the chances of developing psoriasis include:
- Infections, especially streptococcal and HIV infections.
- Certain medicines, such as drugs for treating heart disease, malaria, or mental health problems.
Diagnosis of Psoriasis
To diagnose psoriasis, your doctor usually examines your skin, scalp, and nails for signs of the condition. They may also ask questions about your health and history, such as whether you:
- Experience symptoms such as itchy or burning skin.
- Had a recent illness or experienced severe stress.
- Take certain medicines.
- Have relatives with the disease.
- Experience joint tenderness.
This information will help the doctor figure out if you have psoriasis, and, if so, identify which type. To rule out other skin conditions that look like psoriasis, your doctor may take a small skin sample to examine under a microscope.
Treatment of Psoriasis
While there is currently no cure for psoriasis, there are treatments that keep symptoms under control so that you can resume daily activities and sleep better. There are different types of treatment, and your doctor will work with you to decide which is best for you, taking into consideration the type of psoriasis you have, how severe it is, where it is on your body, and the possible side effects of medications. Your treatment may include the following.
- Topical therapies. Creams, ointments, lotions, foams, or solutions, especially those containing corticosteroids, are commonly used to treat people with mild to moderate disease. Other topical therapies include vitamin D-based medicines, retinoids (related to vitamin A), coal tar, and anthralin (another tar product).
- Injected or oral therapies.
- Methotrexate. This medicine is in a class called antimetabolites, and it is available in an oral or injected form. It suppresses the immune system and slows down cell growth and division.
- Retinoids. These compounds, which are related to vitamin A, may help some people with moderate to severe psoriasis. They can be used in combination with phototherapy.
- Biologic response modifiers. These medications are injected and block specific immune molecules, helping to decrease or stop inflammation.
- Immunosuppressants. These medicines are normally used for severe cases, and they work by suppressing the immune system.
- Phosphodiesterase 4 (PDE4) inhibitors. These target enzymes inside immune cells and suppress the rapid turnover of skin cells and inflammation.
This treatment involves having a doctor shine an ultraviolet light on your skin in their office. A doctor may also prescribe a home ultraviolet light unit. Phototherapy is usually used when large areas of the skin are affected by the disease.
Who Treats Psoriasis?
Psoriasis is treated by:
- Dermatologists, who specialize in conditions of the skin, hair, and nails. You may want to find a dermatologist that specializes in treating psoriasis.
Other health care providers who may be involved in your care include:
- Mental health professionals, who provide counseling and treat mental health disorders, such as depression and anxiety.
- Primary health care providers, including family doctors, internists, or pediatricians.
Living With Psoriasis
Psoriasis can affect a person’s day-to-day life, including work and sleep. However, health care providers understand the impact of the disease and can work with you to help reduce the symptoms. In addition to going to your doctor regularly, here are some things you can do to help manage your symptoms:
- Keep your skin well moisturized. Bathe in lukewarm water and use mild soap that has added oils. After bathing, apply heavy moisturizing lotions while your skin is still damp.
- Maintain a healthy weight. Obesity makes the symptoms of psoriasis worse.
- If you smoke, work with your doctor to make a plan to quit. Studies have shown that the more a person smokes, the worse the symptoms tend to be.
- Moderate your use of alcohol. Some studies suggest that excessive alcohol consumption aggravates symptoms.
- Expose your skin to small amounts of sunlight. Limited sunlight can alleviate symptoms, but too much can make them worse, so consult your doctor for advice.
- Avoid known triggers. Try to identify things that trigger psoriasis flares and work to avoid them. Some people have found that stress, cold weather, skin injuries, certain medicines, and infections spark flares.
- Join a support group or visit a mental health provider. The scaly patches of skin can make many people feel self-conscious about their appearance. Psoriasis can affect a person’s mental health, increasing the risk of anxiety and depression. Seeking out support can help you learn more about coping and living with the disease.
Research Progress Related to Psoriasis
The NIAMS supports translational and clinical research on psoriasis at universities and other organizations throughout the country. Researchers work to understand what causes psoriasis, to identify new treatment strategies, and to uncover other conditions associated with the disease. Following are some examples of the types of studies they are working on.
- To learn more about what causes psoriasis, researchers are performing genetic analyses of people with the disease. The findings may fill some of the gaps in our understanding of how psoriasis starts, and lead to the identification of new drug targets.
- The human microbiome, the collection of all the microbes that live in and on the human body, interacts with the immune system in complex ways. Scientists are studying the makeup of the microbiome in psoriasis patients and how it may affect psoriatic disease outcomes.
- Other researchers are looking for ways to calm the immune system by using small molecules to block the activity of T cells or proteins that promote inflammation. These small molecules may form the basis of new medicines to treat the disease.
- Bacteria have evolved proteins to combat human immune mechanisms. Scientists are testing the efficacy of some of these bacterial proteins in treating psoriasis-like disease in mice.
- Most people with psoriasis develop it as adults, so the understanding of how to treat children is less developed. Scientists are applying artificial intelligence methods to identify disease patterns common to pediatric patients. This research may reveal subgroups of patients that respond better to certain therapies, enabling doctors to tailor treatments to individuals.
- People with psoriasis have a greater risk of other diseases such as diabetes, obesity, and heart problems, and researchers are trying to find out if there are shared genetic risk factors among these diseases. This information will help doctors better assess each patient’s risks and personalize their treatment.