What causes psoriasis?

‘Why do I have psoriasis?’ is a common question that the young people we talked to had thought about. Some had been diagnosed when they were little and didn’t know much about the skin condition until they were older. Sofia’s parents and doctor found it easiest to describe psoriasis as dry skin when she was little. Doctors may have told the person’s parents but unless it had since been explained to the young person, many didn’t know about the underlying causes. Ella learnt that psoriasis is related to the immune system during secondary school – she says it “never transitioned over to my parents telling me about it because I've had it like basically my whole life”.
Normally, new skin cells are produced, moved through the layers of the skin and flake off every 3-4 weeks. In psoriasis, this process happens much quicker (only a few days). This means that the skins cells aren’t fully developed and layer up on the surface of the skin, which leads to the psoriasis symptom of skin flaking. Health professionals think this difference in the pace of the skin cycle happens because some cells and processes in the immune system become over-active and this causes inflammation (swelling) and scaling on the skin. This process can sometimes affect joints too, causing psoriatic arthritis.
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The exact reasons why some people develop psoriasis (i.e. why they develop inflammation and scaling on the skin) is not fully known. Megan found it helpful to think about there being a “switch” for psoriasis which some of her treatments helped to ‘turn off’ but “the switch is still there… it could come back at any time”. What triggers the psoriasis ‘switch’ to turn on in the first place is unclear and seems to vary from person to person (see here for more about triggers). 

Genetics as a possible cause was mentioned by many of the people we talked to. Some knew of family members who also had psoriasis or another skin condition. Sofia learnt about genetics at school and used to joke that it was her dad’s fault because his side of the family have a history of skin conditions. Others were the only person in their family to develop psoriasis. Hannah. Adam and Zara had heard that children with psoriasis sometimes ‘grow out’ of it, but this hadn’t happened for them.
Doctors usually explained a bit about psoriasis at appointments and a few people had also looked up about the causes online. Lisa used her university library to search for medical articles about causes and triggers, but found it confusing. Adam thinks it would be useful to know more about current research on psoriasis, including on causes and treatments.
Some people talked about psoriasis and its causes to others. Sometimes this was because they had been asked a question or in response to a comment made about their psoriasis. Megan says she became better at explaining it as she got older and understood more. Most people felt others didn’t know about psoriasis and often thought it was something they could catch (contagious). Even if comments are made out of ignorance, they can still cause upset. This includes other people's incorrect assumptions that psoriasis was because the person didn’t take care of themselves, had a bad diet or an unhealthy lifestyle. Instead, as Steven said, psoriasis is “not your fault”. Some people found it tricky explaining psoriasis in ways that others would understand and accept. Lola thinks calling it ‘a chronic disease’ “sounds really gruesome or horrible” – she prefers to say “it’s your skin making more skin”. Steven put a positive spin on the increased skin cell production of psoriasis as his body doing 'too much'. Some people thought it was important to explain that psoriasis is about the immune system, not just the skin.


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