Psoriasis is a common inflammatory disease that affects around 1.8 million people in the UK and 125 million people worldwide. August is Psoriasis Awareness Month, an event that aims to educate people about the disease, its causes and the various treatment methods available [1, 2].

Psoriasis presents as scaly plaques on the skin [3]. Although psoriasis primarily affects the skin, it is systemic and associated with coexisting conditions, such as psoriatic arthritis, cardiovascular disease and diabetes [1].

People living with psoriasis may be undertreated and can experience negative psychological and social effects. This has a strong impact on their quality of life and highlights the need to raise awareness of the condition [4].

Psoriasis and its causes

Psoriasis is caused by a combination of genetic, immunological and environmental factors [3]. Keratinocytes (skin cells) activate the immune system and immune cells release proteins called cytokines [5]. IL-17 and IL-23 are cytokines that play a key role in the development of psoriasis [6]. They cause chronic inflammation and hyperproliferation of the epidermis, forming a thick build-up of skin called plaques (see Figure 1) [7]. Plaques present as scaly and red on lighter skin but may appear dark brown or purple and scaly on darker skin [8].

The chronic and sustained inflammation is systemic and can cause other inflammatory conditions, such as psoriatic arthritis [9].

Figure 1. Types of psoriasis [7]

Psoriatic arthritis

Psoriatic arthritis is a chronic inflammatory disease that can occur in patients with psoriasis. It is a progressive disease characterised by chronic inflammation in the joints, which can lead to severe joint damage. These outcomes can be prevented, highlighting the need for early diagnosis and monitoring for coexisting conditions [9].

Prevalence

In the UK, psoriasis is most prevalent in white people [10]. However, the disease may be underdiagnosed in people of colour owing to differences in clinical presentation [11]. The condition is more common in high-income countries with older populations, with Australia being the country with the highest prevalence (1.88%) and Taiwan the country with the lowest (0.05%) [12, 13].

Although men and women are affected equally [10], earlier onset is seen in women [12]. The disease burden is greatest in the 60–69 years age group [14].

Symptoms

Skin-related symptoms	Systemic symptoms
Plaques	Fever
Itchy skin	Malaise
Discoloured skin (red, purple, dark brown)	Joint pain or swelling
Blisters with pus (in severe cases)	Weight loss

Table 1. Skin-related and systemic symptoms of psoriasis [7, 15]

Diagnosis

The diagnosis of psoriasis involves an assessment of the skin and use of scores to measure disease severity and impact on quality of life [15].

A doctor may also ask questions about joint symptoms during the assessment, although patients would likely be referred to a specialist for the diagnosis of comorbidities, e.g. a rheumatologist would diagnose psoriatic arthritis [16].

Treatment options and challenges

Although there is no cure, several management options are available [17]. Topical corticosteroids are used to treat mild psoriasis. They work by reducing inflammation and slowing down the production of skin cells [3].

Immunosuppressants are oral medications prescribed for the treatment of moderate to severe psoriasis. Immunosuppressants slow down the immune system, which helps to reduce inflammation [18].

Biologics are also used as a treatment for psoriasis. They inhibit the cytokines involved in inflammation [3].

Although current treatments are effective in the management of psoriasis, not everyone responds well, and people can experience treatment failure [3]. For this reason, further improvement of therapeutic options for psoriasis is needed.

There are several psoriasis treatments (in particular, biologics) that are currently being investigated in clinical trials [3].

How can you help?

Fundraising

You can support or get involved in fundraising events. Visit the Psoriasis Association website for more information [19].

The information in this article is not intended or implied to be a substitute for professional medical advice, diagnosis or treatment. All content is for general information purposes only. Always seek the guidance of your doctor or other qualified healthcare professional with any questions you may have regarding your health or medical condition.

References

1. Bu J, Ding R, Zhou L et al. Epidemiology of psoriasis and comorbid diseases: A narrative review. Front Immunol 2022; 13: 880201.
2. Psoriasis Association. About psoriasis. Available at: https://www.psoriasis-association.org.uk/about-psoriasis. Accessed August 2024.
3. Lee HJ and Kim M. Challenges and future trends in the treatment of psoriasis. Int J Mol Sci 2023; 24 (17): 13313.
4. Bulat V, Šitum M, Delaš Aždajić M et al. Study on the impact of psoriasis on quality of life: Psychological, social and financial implications. Psychiatr Danub 2020; 32 (Suppl 4): 553–561.
5. Tokuyama M and Mabuchi T. New treatment addressing the pathogenesis of psoriasis. Int J Mol Sci 2020; 21 (20): 7488.
6. Campanati A, Marani A, Martina E et al. Psoriasis as an immune-mediated and inflammatory systemic disease: From pathophysiology to novel therapeutic approaches. Biomedicines 2021; 9 (11): 1511.
7. Dhabale A and Nagpure S. Types of psoriasis and their effects on the immune system. Cureus 2022; 14 (9): e29536.
8. National Psoriasis Foundation. Skin of color resource center. Available at: https://www.psoriasis.org/skin-of-color-resource-center/. Accessed August 2024.
9. Azuaga AB, Ramírez J and Cañete JD. Psoriatic arthritis: Pathogenesis and targeted therapies. Int J Mol Sci 2023; 24 (5): 4901.
10. National Institute for Health and Care Excellence. Psoriasis briefing paper. Available at: https://www.nice.org.uk/guidance/qs40/documents/psoriasis-briefing-paper2. Accessed August 2024.
11. National Psoriasis Foundation. Psoriasis statistics. Available at: https://www.psoriasis.org/psoriasis-statistics/. Accessed August 2024.
12. Raharja A, Mahil SK and Barker JN. Psoriasis: A brief overview. Clin Med (Lond) 2021; 21 (3): 170–173.
13. Parisi R, Iskandar IYK, Kontopantelis E et al. National, regional, and worldwide epidemiology of psoriasis: Systematic analysis and modelling study. BMJ 2020; 369: m1590.
14. Damiani G, Bragazzi NL, Karimkhani Aksut C et al. The global, regional, and national burden of psoriasis: Results and insights from the Global Burden of Disease 2019 study. Front Med (Lausanne) 2021; 8: 743180.
15. National Institute for Health and Care Excellence. Psoriasis: How should I assess a person with suspected psoriasis? Available at: https://cks.nice.org.uk/topics/psoriasis/diagnosis/assessment/. Accessed August 2024.
16. British Skin Foundation. Psoriasis. Available at: https://knowyourskin.britishskinfoundation.org.uk/condition/psoriasis/. Accessed August 2024.
17. Psoriasis Association. Treatments for psoriasis. Available at: https://www.psoriasis-association.org.uk/treatments-for-psoriasis. Accessed August 2024.
18. National Health Service. About methotrexate. Available at: https://www.nhs.uk/medicines/methotrexate/about-methotrexate/. Accessed August 2024.
19. Psoriasis Association website. Available at: https://www.psoriasis-association.org.uk/. Accessed August 2024.

Author: Hafsa Hersi Intern Porterhouse Medical