Psoriasis is an autoimmune condition that causes thick, scaly plaques to form on the skin. There is currently no cure, but treatments may help people reduce the frequency and severity of psoriasis flares.

Psoriasis happens when the immune system boosts the production of skin cells in the body.

A skin cell typically grows and then falls off within 1 month. However, in psoriasis, skin cells grow in 3–4 days and pile up on the skin in plaques rather than falling off.

This causes inflammation that may lead to itchy, uncomfortable, and sometimes painful lesions on the skin surface.

About 7.5 million adults in the United States have some type of psoriasis. The condition is equally common among males and females.

The two peak age ranges for psoriasis onset are 15–25 and 50–60 years old, but it may happen at any age, including in childhood.

This article will look at the symptoms, types, and causes of psoriasis, as well as ways to manage the symptoms.

Psoriasis causes a buildup of skin cells on the skin’s surface. This leads to thick plaques of skin that may be dry, scaly, and raised.


Symptoms of psoriasis typically come and go. Flare-ups are periods when a person’s symptoms get worse, and remission is a period when they subside or clear. Remission periods typically last 1–12 months at a time.

However, the duration of flares and remission periods is challenging to predict.


A person’s symptoms may range from mild to severe depending on the type of psoriasis, the location, and the severity of symptoms.

According to the National Psoriasis Foundation:

  • Mild psoriasis covers less than 3% of the body.
  • Moderate psoriasis covers 3–10% of the body.
  • Severe psoriasis covers more than 10% of the body.

About 25% of people with the condition have moderate-to-severe psoriasis.

There are several types of psoriasis. The severity and location of symptoms may vary depending on the type a person has.

Plaque psoriasis

Plaque psoriasis occurs in 80–90% of people with psoriasis. It presents as raised and inflamed lesions but may vary in appearance depending on a person’s skin tone:

  • On light skin tones: pink or red lesions with silver-white scales
  • On medium skin tones: coral-colored plaques with silver-white scales
  • On dark skin tones: purple or dark brown plaques with gray scales

Plaque psoriasis lesions most often occur on the trunk, buttocks, scalp, and extremities. However, they may appear anywhere on the body.

Inverse psoriasis

Inverse psoriasis is a type of psoriasis that develops in skin folds and commonly affects:

  • the armpits
  • the groin
  • the areas under the breasts
  • other skin folds, such as those around the genitals and buttocks

Inverse psoriasis typically produces lesions without the scales that occur in plaque psoriasis. The lesions might be smooth and shiny.

Irritation from rubbing and sweating can make this type of psoriasis worse due to its location in skin folds and sensitive areas. It is more common among people with overweight or with deep skin folds.

Erythrodermic psoriasis

Erythrodermic psoriasis is a rare type of psoriasis that affects 1–2.25% of people with psoriasis.

A person may have large areas of inflammation across the body that could cause severe itching, pain, and large-scale skin shedding.

This type of psoriasis also disrupts the body’s chemical balance. This may lead to severe complications that could require medical attention, including:

People with symptoms of this condition should contact a doctor right away. They may also need to spend time in the hospital.

Guttate psoriasis

Guttate psoriasis occurs in less than 30% of people with psoriasis. It is more common in children and adolescents than in adults.

This type of psoriasis causes small, individual spots on the skin. They are not usually as thick or crusty as the lesions in plaque psoriasis.

A range of conditions may trigger guttate psoriasis, including:

Guttate psoriasis may resolve without treatment and never return. However, it is possible for the condition to clear up and reappear later as patches of plaque psoriasis.

Pustular psoriasis

Pustular psoriasis is a rare form of psoriasis that appears as white pustules, or blisters of pus, surrounded by inflamed skin. It can affect specific areas of the body, such as the hands and feet, or present more generally. It is not an infection, and it is not contagious.

A doctor will diagnose psoriasis by assessing a person’s symptoms and asking about their personal and family history. In some cases, a doctor may carry out a skin biopsy to rule out other conditions, such as eczema.

Healthcare professionals may also use the following assessment methods to determine the severity of a person’s psoriasis symptoms:

  • A body surface area (BSA) assessment looks at how much of a person’s body psoriasis is affecting.
  • The Psoriasis Area and Severity Index (PASI) uses a score based on skin hardening, scaling, and discoloration to determine a person’s psoriasis severity at one point in time.
  • The Dermatology Life Quality Index assesses the impact of symptoms on a person’s quality of life.
SeverityBSAPASI score
mildless than 3%0–4
severemore than 10%10+

Psoriasis is an autoimmune condition that affects the immune system.

The immune system produces T cells to protect the body against infectious agents.

However, in a person with psoriasis, triggers may cause the immune system to mistakenly target healthy cells. T cells respond to a trigger as if they are fighting an infection or healing a wound, producing chemicals that cause inflammation.

In psoriasis, this autoimmune activity leads to the excessive growth of skin cells, which build up and form plaques.

Common triggers of psoriasis include:

  • stress and anxiety
  • skin injuries such as scratches, sunburn, and bug bites
  • cold, dry weather
  • infections
  • hormonal changes

Medications that may trigger a psoriasis flare include:

  • lithium
  • beta-blockers
  • antimalarials
  • interferons
  • imiquimod
  • angiotensin-converting enzyme inhibitors
  • terbinafine
  • tetracycline
  • nonsteroidal anti-inflammatory drugs (NSAIDs)
  • fibrate drugs

Both external and internal factors may increase a person’s risk of developing psoriasis.

Inflammatory bowel disease (IBD)

IBD is a group of chronic conditions, including ulcerative colitis and Crohn’s disease, that cause inflammation and ulcers in the digestive tract.

Certain medications used to help treat psoriasis, such as interleukin-17 inhibitors and tumor necrosis factor alpha blockers, may worsen or induce symptoms of IBD.

It is important for a person with psoriasis to tell a doctor if they have IBD so the doctor can develop a treatment plan that is right for them.


Genetics may play an important role in the formation of psoriasis. Studies have found more than 60 genetic markers linked to Th17 cell activation, which is a key component of inflammation in psoriasis.

Around 40% of people with psoriasis or psoriatic arthritis have a family history of either condition.


In younger people, psoriasis may flare after a common infection, such as strep throat, bronchitis, or tonsillitis.

Nearly one-third of people with psoriasis develop it in childhood.

Other risk factors

Other risk factors for developing psoriasis include:

  • cardiovascular disease
  • metabolic syndrome
  • trauma to the skin
  • hypertension
  • diabetes
  • smoking
  • excessive alcohol consumption
  • infection
  • obesity

Psoriasis may develop into other health problems that could affect the bones, muscles, and metabolic system.

About 1 in 3 people with psoriasis develop psoriatic arthritis (PsA) within 5–10 years of receiving a psoriasis diagnosis. However, arthritis is present before psoriasis in 13–17% of cases.

PsA is a lifelong autoimmune disease that commonly appears in people 30–50 years old.

It may cause pain, stiffness, and inflammation in a person’s joints and progressively damage them.

People with psoriasis may also be at a higher risk of developing:

There is currently no cure for psoriasis, but several treatments are available to help reduce symptoms and help people cope with this lifelong condition.

Treatment depends on the type and severity of psoriasis, as well as a person’s overall health.

A doctor will tailor a treatment plan for each person.


Some over-the-counter remedies may help relieve symptoms of mild psoriasis:

  • Coal tar may help soothe plaque psoriasis itching and lesions on the scalp, palms, and soles.
  • Hydrocortisone creams may help reduce inflammation and soothe itching.
  • Salicylic acid may help reduce swelling and remove scales, often in people with scalp psoriasis.
  • Anti-itch agents, including products containing calamine, hydrocortisone, camphor, or menthol, can help reduce itching.

Topical therapies

A doctor may prescribe topical treatments, which a person applies directly to the skin. They are usually the first-line treatment for mild-to-moderate symptoms in people without PsA.

Topical treatments aim to:

  • slow down the growth of skin cells
  • reduce inflammation
  • soothe itching or discomfort

Topical treatment options include:

Systemic therapies

Several types of systemic therapies work throughout the body to help reduce:

  • inflammation
  • disease progression
  • regularity of flares

A doctor may prescribe them to:

  • treat moderate-to-severe psoriasis
  • treat symptoms that affect a person’s face, hands, or genitals
  • help prevent joint damage in people with PsA

Biologics are protein-based drugs that target T cells and immune proteins to prevent inflammation and skin cell overproduction.

Examples include:

  • adalimumab (Humira)
  • certolizumab (Cimzia)
  • infliximab (Remicade)
  • ustekinumab (Stelara)
  • etanercept (Enbrel)
  • secukinumab (Cosentyx)

Janus kinase (JAK) inhibitors are a type of systemic therapy to block the gene transcription of certain cytokines, which may help reduce inflammation in the immune system.

Three types of JAK inhibitors have approval for clinical use and may be useful in treating psoriasis:

  • tofacitinib (Xeljanz)
  • baricitinib (Olumiant)
  • ruxolitinib (Jakafi)

Some healthcare professionals currently prescribe baricitinib off-label to help treat psoriasis. The Food and Drug Administration (FDA) has approved baricitinib to treat alopecia areata, atopic dermatitis, rheumatoid arthritis, and COVID-19.

Because biologics and JAK inhibitors are expensive, a person should speak with their insurance provider, if they have one, to see whether their insurance covers these medications.

Alternatively, a person can speak with a doctor about other options that could be more affordable for self-payers, such as:

If none of these systemic therapies work, a doctor may prescribe certain medications off-label. However, this is now a less common approach.


Phototherapy involves regularly exposing the skin to certain lights and lasers to help:

  • slow cell growth
  • suppress immune activity
  • reduce irritation

People typically receive this treatment in a phototherapy center under medical supervision. However, if their initial treatment is successful, some people may carry out phototherapy at home using a lightbox or handheld device.

Some people may also need to take psoralen pills before exposure to make their skin more sensitive to light. This combined therapy is known as PUVA.

However, research suggests that people who receive more than 250 PUVA sessions may be at risk of developing skin cancer.

Anyone who has coexisting conditions that make them sensitive to light, such as lupus or previous instances of skin cancer, should not use phototherapy.

Some strategies may help a person reduce their risk of psoriasis flares, such as:

  • recognizing and avoiding food triggers
  • making efforts to maintain a healthy weight
  • regularly moisturizing the skin
  • traveling to a sunny climate during the winter
  • reducing stress, perhaps through practices such as yoga, exercise, and meditation
  • avoiding smoking and excessive alcohol consumption
  • using topical home remedies to reduce itching

Eating an anti-inflammatory diet may also help a person manage their symptoms and reduce the risk of developing complications.

People with psoriasis can benefit from eating a varied, healthy diet, which may involve:

  • limiting alcohol intake
  • prioritizing lean protein sources such as chicken breast
  • eating fish rich in omega-3 fatty acids
  • reducing gluten intake, if a person has a gluten allergy
  • avoiding pro-inflammatory foods such as those containing simple carbohydrates and saturated fats

Below are some frequently asked questions about psoriasis.

What is the main cause of psoriasis?

Experts are unsure exactly what causes psoriasis. The condition can run in families, so a person with a close relative with psoriasis is more likely to develop it. However, not everyone with an affected relative develops psoriasis. Experts believe that exposure to certain triggers may be necessary for it to develop.

Psoriasis is an autoimmune condition that occurs when T-cells in the immune system mistakenly attack skin cells. This causes the body to grow new skin cells too often, resulting in the thickened skin characteristic of psoriasis.

Psoriasis is not contagious and cannot spread from one person to another.

What deficiency causes psoriasis?

Studies show possible connections between vitamin deficiencies and psoriasis.

  • Vitamin D: A 2018 review reported that 14 out of 20 studies showed a connection between vitamin D deficiency and psoriasis.
  • Vitamin E: Vitamin E deficiency may play a role in psoriasis, vitiligo, atopic dermatitis, and acne.
  • Vitamin A: A deficiency in vitamin A may contribute to psoriasis and fungal skin infections.

Read more about vitamins and psoriasis.

Is there a trigger for psoriasis?

Common factors that trigger psoriasis symptoms include:

  • stress and anxiety
  • skin injuries
  • prolonged sun exposure
  • cold, dry weather
  • infections
  • hormonal changes

What clears psoriasis fast?

There are no proven “quick-fixes” to clear psoriasis. What works for one person may not work for another.

People can try the following treatments:

  • phototherapy, which is regularly exposing the skin to ultraviolet light
  • topical creams and ointments
  • systemic drugs that people take orally
  • avoiding stress, eating a nutritious diet, and doing regular physical activity

Does psoriasis go away?

Psoriasis can go away for months or years, but it usually flares up again at some point. Periods without symptoms are called “remission”. According to the American Academy of Dermatology, most remission periods last 1–12 months.

Learn more about psoriasis remission.

Where does psoriasis usually start?

Psoriasis plaques may occur anywhere on the body, but they typically appear on the following areas:

  • elbows
  • knees
  • lower back
  • scalp

The location of plaques may vary depending on the type of psoriasis a person has.

How can someone stop psoriasis from spreading?

People can make lifestyle changes to prevent psoriasis from spreading, such as:

  • limiting alcohol intake
  • eat a balanced, anti-inflammatory diet
  • reduce stress, such as with meditation or yoga
  • maintain a moderate weight
  • moisturize skin regularly
  • avoid known triggers

How long do psoriasis flare-ups last?

Psoriasis flares can be unpredictable and vary in duration. However, psoriasis is a lifelong condition. Remission periods between flares typically last 1–12 months.

Psoriasis is an autoimmune condition that causes the body to produce skin cells at an increased rate. These cells then build up on the skin, forming plaques.

There are multiple types of psoriasis. The symptoms range from small, itchy papules to severe rashes that can cover large parts of the body.

Although the root cause of psoriasis is unclear, understanding which triggers cause flare-ups may help a person manage their symptoms. Other management options include topical ointments, systemic medications, phototherapy, and lifestyle changes.

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