What Is Psoriasis?

If you're struggling with red, scaly patches on your skin that just won't go away, you might be wondering if you have psoriasis. In this article, we'll explore what psoriasis is, what may be causing it, and what you can do to manage its symptoms.

Psoriasis is a chronic skin condition that affects millions of people worldwide and can be a significant source of discomfort and embarrassment. Psoriasis causes red, scaly patches on the skin. It is a non-contagious, autoimmune disease that occurs when the immune system attacks healthy skin cells, leading to an overproduction of new skin cells. The build-up of these skin cells creates thick, red, and scaly patches on the skin's surface. 

In the following sections, we'll take a closer look at the causes, signs and symptoms of psoriasis, as well as the available treatment options. So, if you're looking for information on psoriasis and how to manage its symptoms, keep reading.


Psoriasis is an autoimmune skin condition that causes scaly patches on the skin. It affects around 2–3% of the global population, with symptoms commonly appearing on the scalp, elbows, knees, and lower back. The symptoms can vary depending on the type of psoriasis in question. While the exact cause is unknown, it is believed to be related to an abnormal immune response causing skin cells to grow too quickly. Although there is no cure for psoriasis, treatments such as topical creams, light therapy, and lifestyle modifications can help manage the symptoms. 

Causes of psoriasis

Psoriasis is a chronic skin condition that causes the skin cells to multiply rapidly, leading to a build-up of cells on the skin's surface. Normally, the body takes about 3-4 weeks to produce new skin cells that gradually move up to the surface and flake off. However, in people with psoriasis, this process is accelerated and takes only 3-7 days, leading to the build-up of immature cells on the skin's surface. The exact cause of this condition is not known, but it is believed to be related to a problem with the immune system, and genes also play an important role. It's important to note that psoriasis is not contagious and cannot be transmitted from one person to another.1,2

Immune System Malfunction

  •  The immune system is responsible for protecting the body against infection and disease.
  • A type of white blood cell called T-cells detect and fight invading germs. However, T-cells mistakenly attack healthy skin cells in individuals with psoriasis, causing the body to produce new skin cells more rapidly than usual.
  • The overproduction of skin cells leads to the formation of the scaly patches characteristic of psoriasis1,2

The exact cause of this immune system malfunction is unknown, but research suggests that genetic and environmental factors may contribute to its development.

Psoriasis has a genetic component, and individuals with a close relative who has the condition are at a higher risk of developing it. Research has identified multiple genes that are associated with psoriasis and that different combinations of these genes may increase the vulnerability to the condition. However, having these genes does not necessarily mean an individual will develop psoriasis.1,2

In addition to genetics, psoriasis can also be triggered by various factors such as:

  • Skin injuries
  • Excessive alcohol consumption
  • Smoking
  • Stress
  • Hormonal changes
  • Certain medications
  • Weather, especially cold or dry weather
  • Throat infections
  •  Other immune disorders.

These triggers can also cause psoriasis flare-ups, which can vary from person to person. For instance, some individuals may experience a psoriasis flare-up during times of high stress, while others may not be affected but may experience a flare-up due to dry weather.1,2

Signs and symptoms of psoriasis

The most typical symptom of psoriasis is the appearance of dry, thick, and raised patches on the skin, often covered with silvery-white scales that cause itchy skin.3

However, psoriasis can present a range of signs and symptoms that may vary depending on:

  • Type of psoriasis
  • Affected body areas
  • Amount of psoriasis present

Types of psoriasis

  1. Plaque psoriasis (psoriasis vulgaris): This is the most common type of psoriasis, affecting around 80% to 90% of people. This type of psoriasis appears as thick, raised patches of skin called plaques that may be covered with a dry, thin, silvery-white coating (scales). The plaques can vary in size and may join together to form larger patches. They typically appear on the scalp, elbows, knees, or lower back, but can develop anywhere on the skin3
  2. Guttate psoriasis: This is a type of psoriasis that is characterised by the sudden appearance of tiny bumps on the skin. These bumps tend to cover a large part of the torso, legs, and arms and may also develop on the face, scalp, and ears. They are small, scaly, and have a salmon-to-pink appearance. Interestingly, this type of psoriasis is temporary and can clear up in a few weeks or months without treatment
  3. Inverse psoriasis: This psoriasis, also known as intertriginous or flexural psoriasis, typically develops in areas where skin touches the skin, such as the armpits, genitals, and creases of the buttocks. The characteristic signs of inverse psoriasis include smooth, red patches of skin that look raw, and there is usually little to no silvery coating. In addition, the affected skin may feel sore or painful3
  4. Pustular psoriasis: This is a type of psoriasis that causes painful, pus-filled bumps that typically appear on the hands and feet. Although the bumps may resemble an infection, they do not contain any bacteria or infectious agents. The affected skin may be red, swollen, and dotted with pus-filled bumps. As the bumps dry out, brown dots and sometimes scales may appear3
  5. Pustular psoriasis (generalized): This rare type of psoriasis, also known as von Zumbusch psoriasis, causes the development of pus-filled bumps all over the skin. It leads to a series of events where the skin suddenly becomes dry, red, and tender, followed by the appearance of pus-filled bumps that cover most of the skin within hours. Afterwards, these bumps break open, and the skin dries out and peels off, leaving behind a smooth surface3
  6. Erythrodermic psoriasis: Erythrodermic psoriasis is a severe and life-threatening type of psoriasis that requires urgent medical care. Signs that someone has developed erythrodermic psoriasis include skin that appears burnt, a high fever, muscle weakness, a rapid pulse, and a severe itch.3
  7. Nail psoriasis: nail psoriasis is particularly common in individuals with plaque psoriasis, where approximately half of the patients experience nail changes at some point. Nail psoriasis can present several different symptoms, including small dents in the nails, discolouration, which can appear as white, yellow, or brown, rough and crumbly nails, and separation of the nail from the nail bed3
  8. Psoriatic arthritis: Psoriasis can cause a type of arthritis known as psoriatic arthritis, which affects the joints. People with severe psoriasis are at higher risk of developing psoriatic arthritis. The symptoms of psoriatic arthritis can be subtle in the beginning; some include swelling and tenderness in a joint, particularly in fingers or toes, heel pain, and swelling above the heel on the back of the leg.3

Management and treatment for psoriasis

Psoriasis treatment is generally effective in managing the condition. Generally, the patients can be treated by their GP; however, in cases where symptoms are severe or not respond well to treatment, patients may be referred to a dermatologist.4

The choice of treatment depends on three main points:4

  • The type of psoriasis
  • The severity of the psoriasis
  • The affected skin area

Typically, mild treatments such as topical creams are initially prescribed, with stronger treatments being recommended afterwards, only if it’s necessary. There is a wide range of treatments available for psoriasis but finding the most effective one can be challenging.4

There are three categories of treatments, and in most cases, a combination of treatments is used:

  • Topical: involves applying creams and ointments to the affected areas.
  • Phototherapy: skin exposed to ultraviolet light.
  • Systemic: oral or injected medications that work throughout the body.

In addition to the medication, it is also crucial for those with psoriasis to identify their triggers in order to manage their condition effectively. Avoiding triggers can help to reduce the frequency and severity of psoriasis flare-ups.4


How is psoriasis diagnosed?

To diagnose psoriasis, doctors typically assess the skin, scalp, and nails for indications of the condition. Additionally, they may ask some questions about your medical history and general health.5

How can I prevent psoriasis?

There is no way to prevent psoriasis, but you may reduce the number of psoriasis flare-ups if you avoid some of the triggers that usually lead to your psoriasis.6

What are the types of psoriasis?

There are many different types of psoriasis, such as plaque psoriasis, guttate psoriasis, inverse psoriasis, pustular psoriasis, pustular psoriasis (generalized), erythrodermic psoriasis, nail psoriasis, and psoriatic arthritis.3

Who is at risk of psoriasis?

Psoriasis can affect anyone, but certain factors may increase the risk of developing this condition. These include genetic predisposition and a weakened immune system. In addition to these factors, psoriasis can also be triggered by skin injuries, excessive alcohol consumption, smoking, stress, hormonal changes, certain medications, weather, especially cold or dry weather, and throat infections.1

How common is psoriasis?

Psoriasis is common, affecting around 2 – 3% of the global population.7

When should I see a doctor?

The National Psoriasis Foundation advises individuals with psoriasis to seek the expertise of a dermatologist. This is particularly important in situations where the condition is flaring up, symptoms are worsening, and the treatments prescribed are ineffective.8


Psoriasis is a chronic skin condition that affects 2-3% of the global population, causing red, scaly patches on the skin. The cause is unknown, but it is believed to be related to an abnormal immune response that causes skin cells to grow too quickly. Genetics plays an important role, as well as factors such as skin injuries, excessive alcohol consumption, smoking, stress, hormonal changes, certain medications, and weather. The condition has different types, with plaque psoriasis being the most common. Although there is no cure, treatments such as topical creams, light therapy, and lifestyle modifications can help manage symptoms.


  1. Psoriasis - Causes. nhs.uk [Internet]. 2018 [cited 2023 Mar 2]. Available from: https://www.nhs.uk/conditions/psoriasis/causes/.
  2. Psoriasis: Causes [Internet]. [cited 2023 Mar 2]. Available from: https://www.aad.org/public/diseases/psoriasis/what/causes.
  3. Psoriasis: Signs and symptoms [Internet]. [cited 2023 Mar 2]. Available from: https://www.aad.org/public/diseases/psoriasis/what/symptoms.
  4. Psoriasis - Treatment. nhs.uk [Internet]. 2017 [cited 2023 Mar 2]. Available from: https://www.nhs.uk/conditions/psoriasis/treatment/.
  5. Branch NSC and O. Psoriasis. National Institute of Arthritis and Musculoskeletal and Skin Diseases [Internet]. 2017 [cited 2023 Mar 2]. Available from: https://www.niams.nih.gov/health-topics/psoriasis.
  6. Prevention [Internet]. [cited 2023 Mar 2]. Available from: https://stanfordhealthcare.org/medical-conditions/skin-hair-and-nails/psoriasis/prevention.html.
  7. Get the Facts About Psoriasis and Psoriatic Arthritis [Internet]. [cited 2023 Mar 2]. Available from: https://www.psoriasis.org/psoriasis-statistics/.
  8. Dermatologists and Psoriasis [Internet]. [cited 2023 Mar 2]. Available from: https://www.psoriasis.org/dermatologist/.
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Joana Carneiro

Masters of Public Health - Escola Nacional de Saúde Pública, Lisboa

Joana is a recent graduate, who has a Degree in Biomedical Sciences and a Master's Degree in Public Health. She has more than two years of experience working as a healthcare professional in both private and public settings and more than 4 years of experience working as a volunteer in a non-profit organization, helping disadvantaged communities. Joana is passionate about public health, specifically about everything related to health education, health communication and health equity.

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