What Is Psoriatic Disease?

Your immune system is designed to keep you healthy by fighting off outside invaders like bacteria, viruses, and other pathogens.

But when you have psoriatic disease, harmless substances activate your immune cells by mistake. This triggers the release of proteins that cause inflammation.

With psoriasis, the activated immune cells travel to your skin.

When this happens, your skin cells start growing too fast.

As they pile up on the surface, the top layer of your skin becomes thick and scaly.

Your blood vessels also expand, sending more blood and more immune cells to your skin.

If you also have psoriatic arthritis, a similar immune response happens inside your body, making your joints and tendons swollen and painful.