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What is psoriatic disease?

Psoriatic disease is the overarching name for a group of conditions that affect the skin and joints due to an overactive immune system. In a healthy body, the immune system plays a key role in fighting off invaders such as harmful bacteria and viruses. In somebody with an autoimmune condition, the immune system will mistakenly attack healthy tissue, which in psoriatic disease is the skin and in some instances the joints and the spine. The conditions psoriasis and psoriatic arthritis are both seen as psoriatic diseases. Here we will focus on the skin aspects of psoriatic disease known as psoriasis, but you can learn more about the joint and spine involvement in psoriatic arthritis (a condition that causes pain, swelling and stiffness in and around the joints and spine) here.

What happens to the skin in psoriatic disease?

Psoriatic disease is an autoimmune condition that, amongst other manifestations, causes the body to make too many skin cells, resulting in the appearance of red, flaky, crusty patches of skin that look as if they are covered in silvery scales. This manifestation is known as psoriasis. Patches of psoriasis can appear anywhere on the body but are most commonly found on the elbows, knees, scalp and lower back.1

There are several different types of psoriasis, including but not limited to:2

  • Plaque psoriasis – the most common form psoriasis, its symptoms include red skin lesions, known as plaques, that are covered in silver scales
  • Guttate psoriasis – causes small sores on the chest, legs and scalp
  • Inverse psoriasis – affects folds or creases in the skin such as the armpits and groin


Symptoms of psoriasis

The main symptoms of plaque psoriasis include thick, red, flaky skin patches, scaling of the skin, itching, and pain. Guttate psoriasis causes sores to appear on the chest, legs and scalp that usually disappear after a few weeks,2 and inverse psoriasis causes smooth red patches to appear in the folds of skin such as the armpits. Alongside the physical symptoms, psoriasis can have a big impact on quality of life, affecting the day-to-day activities and well-being of the people with the condition.

Due to the systemic nature of the condition, which means that it can affect the entire body, people with psoriasis are also more likely to suffer from other inflammatory conditions. Up to 40% of people find their joints are affected3 – a painful condition known as psoriatic arthritis. Other comorbidities, or diseases that are more likely to occur simultaneously with psoriasis, include diabetes, heart disease4 and ankylosing spondylitis.5

Impact of skin symptoms on quality of life  

Living with psoriatic disease can have a big impact on the lives of people with the condition, apart from experiencing symptoms alone. For example, 51% reported feeling self-conscious because of their psoriasis, 54% reported feeling depressed, and 10% have experienced discrimination at work.6,7

What causes the skin symptoms of psoriatic disease?

In the case of psoriasis, the skin manifestation in psoriatic disease, symptoms may start when a combination of environmental and genetic factors disrupt the normal lifecycle of skin cells.8

Skin cells grow within the deeper layers of the skin, and then move to the surface as the outermost layers flake off, which in total takes around one month. In psoriasis, the immune system mistakenly attacks healthy skin cells, causing the process to accelerate and dead skin cells to build up on the skin's surface.9

Who is affected by psoriasis?

If you have experienced psoriasis as part of psoriatic disease, know that you are not alone. Psoriasis is far more common than most people think, and as many as 125 million people worldwide live with the condition – that’s 2-3% of the entire population! The first signs and symptoms of psoriasis often appear between the ages of 15 and 25, but they can develop at any age.10 Psoriasis affects men and women equally.8

Diagnosing psoriasis

The symptoms of psoriatic disease can be diagnosed in different ways. For psoriasis, it can usually be diagnosed by a general practitioner (GP) based on the appearance of your skin. In some cases, your GP may refer you to a specialist called a dermatologist, a doctor who is specialised in treating skin conditions, to confirm the diagnosis. In a small number of cases, they may also take a small sample of skin to determine the exact type of psoriasis.1 After diagnosis, you may also be referred to a dermatologist for further follow up and treatment.


Here we will look at treatment options available specifically for the skin elements of psoriatic disease. 

There is no cure for psoriasis but there are treatment options available that aim to improve symptoms.

The first treatment options for psoriasis tend to be creams and ointments that can be applied to the skin. Another treatment option is phototherapy, where skin is exposed to certain types of ultraviolet light. For more severe cases, systemic treatments (oral and injected medicines that work throughout the whole body rather than targeting one area, e.g. biologic medicines11) may be considered. Another treatment option is biologic medicines. 


NHS. Overview Psoriasis. 2018. Available at: Last accessed June 2019

2 NHS. Symptoms Psoriasis. 2018. Available at: Last accessed June 2019

3 Mease, P. et al. Managing Patients with Psoriatic Disease: The Diagnosis and Pharmacologic Treatment of Psoriatic Arthritis in Patients with Psoriasis. Drugs 2014; 74: 423-441

4 Web MD. Psoriasis, Heart Disease, and Diabetes: What's the Link? 2010. Available at: Last accessed June 2019

5 Everyday Health. 5 Health Conditions Related to Ankylosing Spondylitis. 2018. Available at: Last accessed July 2019

6 Krueger G., Koo J., Lebwohl M., et al. The Impact of Psoriasis on Quality of Life Results of a 1998 National Psoriasis Foundation Patient-Membership Survey. JAMA Dermatology. 2001. 137(3):280-284

7 Novartis. Clear About Psoriasis Patient Survey. An Online Global Patient Study. April 2016

8 British Skin Foundation. Psoriasis. 2019. Available at: Last accessed: June 2019

9 NHS. Causes Psoriasis. 2018. Available at: Last accessed June 2019

10 Psoriasis Foundation. Statistics. 2019. Available at: Last accessed June 2019

11 NHS. Treatment Psoriasis. 2018. Available at: Last accessed June 2019

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