What does that mean, “autoimmune”? It means the immune system gets turned on automatically to launch an inflammatory response against your own body, instead of fighting against nasty bacteria and viruses. In the case of psoriatic disease and conditions like psoriasis and PsA, the immune system targets the skin and joints. This abnormal immune response causes inflammation in the skin, resulting in the red, itchy and scaly patches of psoriasis known as plaques. In PsA, it is inflammation in the body that leads to pain and swelling of joints and tendons.

The details of this process, and particularly why it gets started in the first place, are still not completely clear to researchers. They are trying to identify the substances that the immune system mistakes for an invader and causes it to turn itself on.

Whatever the cause, the result of the immune system being “turned on” against healthy tissue is not positive for your body. In fact, the body’s response is similar to what it does when it attacks real invaders – it tries to get rid of them by using T cells to begin an inflammatory attack. When you’re sick or injured, this can be a helpful response, triggering inflammation and causing blood vessels to expand and create the familiar redness of inflammation we can see.


However, when the response is autoimmune and unwelcome, as is the case with psoriasis and PsA, we see this inflammation happen on the skin and in the joints.

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