Inflammation and redness around the scales is fairly common. Typical psoriatic scales are whitish-silver and develop in thick, red patches. Sometimes, these patches will crack and bleed.

Psoriasis is the result of a sped-up skin production process. Typically, skin cells grow deep in the skin and slowly rise to the surface. Eventually, they fall off. The typical life cycle of a skin cell is one month.

In people with psoriasis, this production process may occur in just a few days. Because of this, skin cells don’t have time to fall off. This rapid overproduction leads to the buildup of skin cells.

Scales typically develop on joints, such elbows and knees. They may develop anywhere on the body, including the:

hands
feet
neck
scalp
face

Less common types of psoriasis affect the nails, the mouth, and the area around genitals.

According to one study, around 7.4 million Americans have psoriasis. It’s commonly associated with several other conditions, including:

type 2 diabetes
inflammatory bowel disease
heart disease
psoriatic arthritis
anxiety
depression

What are the different types of psoriasis?

There are five types of psoriasis:
Plaque psoriasis

Plaque psoriasis is the most common type of psoriasis.

The American Academy of Dermatology (AAD) estimates that about 80 percent of people with the condition have plaque psoriasis. It causes red, inflamed patches that cover areas of the skin. These patches are often covered with whitish-silver scales or plaques. These plaques are commonly found on the elbows, knees, and scalp.

Guttate psoriasis

Guttate psoriasis is common in childhood. This type of psoriasis causes small pink spots. The most common sites for guttate psoriasis include the torso, arms, and legs. These spots are rarely thick or raised like plaque psoriasis.

Pustular psoriasis

Pustular psoriasis is more common in adults. It causes white, pus-filled blisters and broad areas of red, inflamed skin. Pustular psoriasis is typically localized to smaller areas of the body, such as the hands or feet, but it can be widespread.

Inverse psoriasis

Inverse psoriasis causes bright areas of red, shiny, inflamed skin. Patches of inverse psoriasis develop under armpits or breasts, in the groin, or around skinfolds in the genitals.

Erythrodermic psoriasis

Erythrodermic psoriasis is a severe and very rare type of psoriasis.

This form often covers large sections of the body at once. The skin almost appears sunburned. Scales that develop often slough off in large sections or sheets. It’s not uncommon for a person with this type of psoriasis to run a fever or become very ill.

This type can be life-threatening, so individuals should see a doctor immediately.

Check out pictures of the different types of psoriasis.

What are the symptoms?

Psoriasis symptoms differ from person to person and depend on the type of psoriasis. Areas of psoriasis can be as small as a few flakes on the scalp or elbow, or cover the majority of the body.

The most common symptoms of plaque psoriasis include:

raised, inflamed patches of skin which appear red on light skin and brown or purple on dark skin
whitish-silver scales or plaques on the red patches or gray scales on purple and brown patches
dry skin that may crack and bleed
soreness around patches
itching and burning sensations around patches
thick, pitted nails
painful, swollen joints

Not every person will experience all of these symptoms. Some people will experience entirely different symptoms if they have a less common type of psoriasis.

Most people with psoriasis go through “cycles” of symptoms. The condition may cause severe symptoms for a few days or weeks, and then the symptoms may clear up and be almost unnoticeable. Then, in a few weeks or if made worse by a common psoriasis trigger, the condition may flare up again. Sometimes, symptoms of psoriasis disappear completely.

When you have no active signs of the condition, you may be in “remission.” That doesn’t mean psoriasis won’t come back, but for now you’re symptom-free.

Is psoriasis contagious?

Psoriasis isn’t contagious. You can’t pass the skin condition from one person to another. Touching a psoriatic lesion on another person won’t cause you to develop the condition.

What causes psoriasis?

Doctors are unclear as to what causes psoriasis. However, thanks to decades of research, they have a general idea of two key factors: genetics and the immune system.

Immune system

Psoriasis is an autoimmune condition. Autoimmune conditions are the result of the body attacking itself. In the case of psoriasis, white blood cells known as T cells mistakenly attack the skin cells.

In a typical body, white blood cells are deployed to attack and destroy invading bacteria and fight infections. This mistaken attack causes the skin cell production process to go into overdrive. The sped-up skin cell production causes new skin cells to develop too quickly. They are pushed to the skin’s surface, where they pile up.

This results in the plaques that are most commonly associated with psoriasis. The attacks on the skin cells also cause red, inflamed areas of skin to develop.

Genetics

Some people inherit genes that make them more likely to develop psoriasis. If you have an immediate family member with the skin condition, your risk for developing psoriasis is higher. However, the percentage of people who have psoriasis and a genetic predisposition is small. Approximately 2 to 3 percent of people with the gene develop the condition, according to the National Psoriasis Foundation (NPF).

Read more about the causes of psoriasis.

Diagnosing psoriasis

Two tests or examinations may be necessary to diagnose psoriasis.

Physical examination

Most doctors are able to make a diagnosis with a simple physical exam. Symptoms of psoriasis are typically evident and easy to distinguish from other conditions that may cause similar symptoms.

During this exam, be sure to show your doctor all areas of concern. In addition, let your doctor know if any family members have the condition.

Biopsy

If the symptoms are unclear or if your doctor wants to confirm their suspected diagnosis, they may take a small sample of skin. This is known as a biopsy.

The skin will be sent to a lab, where it’ll be examined under a microscope. The examination can diagnose the type of psoriasis you have. It can also rule out other possible disorders or infections.

Most biopsies are done in your doctor’s office the day of your appointment. Your doctor will likely inject a local numbing medication to make the biopsy less painful. They will then send the biopsy to a lab for analysis.

When the results return, your doctor may request an appointment to discuss the findings and treatment options with you.

Psoriasis triggers: Stress, alcohol, and more

External “triggers” may start a new bout of psoriasis. These triggers aren’t the same for everyone. They may also change over time for you.

The most common triggers for psoriasis include:

Stress

Unusually high stress may trigger a flare-up. If you learn to reduce and manage your stress, you can reduce and possibly prevent flare-ups.

Alcohol

Heavy alcohol use can trigger psoriasis flare-ups. If you excessively use alcohol, psoriasis outbreaks may be more frequent. Reducing alcohol consumption is smart for more than just your skin too. Your doctor can help you form a plan to quit drinking if you need help.

Injury

An accident, cut, or scrape may trigger a flare-up. Shots, vaccines, and sunburns can also trigger a new outbreak.

Medications

Some medications are considered psoriasis triggers. These medications include:

lithium
antimalarial medications
high blood pressure medication

Infection

Psoriasis is caused, at least in part, by the immune system mistakenly attacking healthy skin cells. If you’re sick or battling an infection, your immune system will go into overdrive to fight the infection. This might start another psoriasis flare-up. Strep throat is a common trigger.

Here are 10 more psoriasis triggers you can avoid.

Treatment options for psoriasis

Psoriasis has no cure. Treatments aim to reduce inflammation and scales, slow the growth of skin cells, and remove plaques. Psoriasis treatments fall into three categories:

Topical treatments

Creams and ointments applied directly to the skin can be helpful for reducing mild to moderate psoriasis.

Topical psoriasis treatments include:

topical corticosteroids
topical retinoids
anthralin
vitamin D analogues
salicylic acid
moisturizer

Systemic medications

People with moderate to severe psoriasis, and those who haven’t responded well to other treatment types, may need to use oral or injected medications. Many of these medications have severe side effects. Doctors usually prescribe them for short periods of time.

These medications include:

methotrexate
cyclosporine (Sandimmune)
biologics
retinoids

Light therapy

This psoriasis treatment uses ultraviolet (UV) or natural light. Sunlight kills the overactive white blood cells that are attacking healthy skin cells and causing the rapid cell growth. Both UVA and UVB light may be helpful in reducing symptoms of mild to moderate psoriasis.

Most people with moderate to severe psoriasis will benefit from a combination of treatments. This type of therapy uses more than one of the treatment types to reduce symptoms. Some people may use the same treatment their entire lives. Others may need to change treatments occasionally if their skin stops responding to what they’re using.

Medication for psoriasis

If you have moderate to severe psoriasis - or if psoriasis stops responding to other treatments - your doctor may consider an oral or injected medication.

The most common oral and injected medications used to treat psoriasis include:

Biologics

This class of medications alters your immune system and prevents interactions between your immune system and inflammatory pathways. These medications are injected or given through intravenous (IV) infusion.

Retinoids

Retinoids reduce skin cell production. Once you stop using them, symptoms of psoriasis will likely return. Side effects include hair loss and lip inflammation.

People who are pregnant or may become pregnant within the next three years shouldn’t take retinoids because of the risk of possible birth defects.

Cyclosporine

Cyclosporine (Sandimmune) prevents the immune system’s response. This can ease symptoms of psoriasis. It also means you have a weakened immune system, so you may become sick more easily. Side effects include kidney problems and high blood pressure.

Methotrexate

Like cyclosporine, methotrexate suppresses the immune system. It may cause fewer side effects when used in low doses. It can cause serious side effects in the long term. Serious side effects include liver damage and reduced production of red and white blood cells.

Diet recommendations for people with psoriasis

Food can’t cure or even treat psoriasis, but eating better might reduce your symptoms. These five lifestyle changes may help ease symptoms of psoriasis and reduce flare-ups:

Lose weight

If you’re overweight, losing weight may reduce the condition’s severity. Losing weight may also make treatments more effective. It’s unclear how weight interacts with psoriasis, so even if your symptoms remain unchanged, losing weight is still good for your overall health.

Eat a heart-healthy diet

Reduce your intake of saturated fats. These are found in animal products like meats and dairy. Increase your intake of lean proteins that contain omega-3 fatty acids, such as salmon, sardines, and shrimp. Plant sources of omega-3s include walnuts, flax seeds, and soybeans.

Avoid trigger foods

Psoriasis causes inflammation. Certain foods cause inflammation too. Avoiding those foods might improve symptoms. These foods include:

red meat
refined sugar
processed foods
dairy products

Drink less alcohol

Alcohol consumption can increase your risks of a flare-up. Cut back or quit entirely. If you have a problem with your alcohol use, your doctor can help you form a treatment plan.

Consider taking vitamins

Some doctors prefer a vitamin-rich diet to vitamins in pill form. However, even the healthiest eater may need help getting adequate nutrients. Ask your doctor if you should be taking any vitamins as a supplement to your diet.

Learn more about your dietary options.

Living with psoriasis

Life with psoriasis can be challenging, but with the right approach, you can reduce flare-ups and live a healthy, fulfilling life. These three areas will help you cope in the short- and long-term:

Diet

Losing weight and maintaining a healthy diet can go a long way toward helping ease and reduce symptoms of psoriasis. This includes eating a diet rich in omega-3 fatty acids, whole grains, and plants. You should also limit foods that may increase your inflammation. These foods include refined sugars, dairy products, and processed foods.

There is anecdotal evidence that eating nightshade fruits and vegetables can trigger psoriasis symptoms. Nightshade fruits and vegetables include tomatoes as well as white potatoes, eggplants, and pepper-derived foods like paprika and cayenne pepper (but not black pepper, which comes from a different plant altogether).

Stress

Stress is a well-established trigger for psoriasis. Learning to manage and cope with stress may help you reduce flare-ups and ease symptoms. Try the following to reduce your stress:

meditation
journaling
breathing
yoga

Emotional health

People with psoriasis are more likely to experience depression and self-esteem issues. You may feel less confident when new spots appear. Talking with family members about how psoriasis affects you may be difficult. The constant cycle of the condition may be frustrating too.

All of these emotional issues are valid. It’s important you find a resource for handling them. This may include speaking with a professional mental health expert or joining a group for people with psoriasis.

Learn more about living with psoriasis.

Psoriasis and arthritis

Between 30 and 33 percent of people with psoriasis will receive a diagnosis of psoriatic arthritis, according to recent clinical guidelines from the AAD and the NPF.

This type of arthritis causes swelling, pain, and inflammation in affected joints. It’s commonly mistaken for rheumatoid arthritis or gout. The presence of inflamed, red areas of skin with plaques usually distinguishes this type of arthritis from others.

Psoriatic arthritis is a chronic condition. Like psoriasis, the symptoms of psoriatic arthritis may come and go, alternating between flare-ups and remission. Psoriatic arthritis can also be continuous, with constant symptoms and issues.

This condition typically affects joints in the fingers or toes. It may also affect your lower back, wrists, knees, or ankles.

Most people who develop psoriatic arthritis have psoriasis. However, it’s possible to develop the joint condition without having a psoriasis diagnosis. Most people who receive an arthritis diagnosis without having psoriasis have a family member who does have the skin condition.

Treatments for psoriatic arthritis may successfully ease symptoms, relieve pain, and improve joint mobility. As with psoriasis, losing weight, maintaining a healthy diet, and avoiding triggers may also help reduce psoriatic arthritis flare-ups. An early diagnosis and treatment plan can reduce the likelihood of severe complications, including joint damage.

Learn more about psoriatic arthritis.

Psoriasis statistics

Around 7.4 million people in the United States have psoriasis.

Psoriasis may begin at any age, but most diagnoses occur in adulthood. The average age of onset is between 15 to 35 years old. According to the World Health Organization (WHO), some studies estimate that about 75 percent of psoriasis cases are diagnosed before age 46. A second peak period of diagnoses can occur in the late 50s and early 60s.

According to WHO, males and females are affected equally. White people are affected disproportionately. People of color make up a very small proportion of psoriasis diagnoses.

Having a family member with the condition increases your risk for developing psoriasis. However, many people with the condition have no family history at all. Some people with a family history won’t develop psoriasis.

Around one-third of people with psoriasis will be diagnosed with psoriatic arthritis. In addition, people with psoriasis are more likely to develop conditions such as:

type 2 diabetes
kidney disease
heart disease
high blood pressure

Though the data isn’t complete, research suggests cases of psoriasis are becoming more common. Whether that’s because people are developing the skin condition or doctors are just getting better at diagnosing is unclear.