The Immune System
Your skin is one barrier to infection, but you also need your immune system to defend against disease. Your immune system is extremely complex, but it has two main functions. The first is to recognise an agent in your body, such as a virus, that may cause disease (this agent is called a ‘pathogen’). The second is to effectively defend your body against the pathogen. Your immune system can develop a memory for certain diseases which means next time, your immune system will be able to respond more quickly. This is how vaccinations against certain diseases work.
Inflammation (redness, swelling and heat) is the result of your immune system responding to injury or disease, and is a necessary part of combating disease or healing of injury.
In conditions like psoriasis the immune system causes an excessive inflammatory response. This response causes the cycle of skin cell production to become faster – in the space of 3 – 4 days, rather than the normal 28 days. The skin cells then build up on the surface of your skin in thick scaly patches.
Psoriasis is an ‘auto-immune’ disease because your immune system starts a response against your body’s own tissues rather than against a pathogen.