Professor Luke O'Neill

Now, that is a really sort of a challenging condition for people because not only do you have psoriasis in your skin, you've also got arthritis, and that means your joints are sore.

Because, of course, arthritis is an immune disease of the joints.

So psoriatic arthritis, you get both.

And that can be very debilitating.

Not only are you getting scaly red patches, but your joints are in agony as well.

And it's slightly different to normal arthritis.

The psoriasis is slightly different as well.

So it's a subtype again.

So in some ways, then, you have four subtypes.

And often in medicine that happens, by the way.

Now, let's say 150 years ago, something like a disease is described, like, say, whatever it might be.

It could be a skin disease.

And then we realize over time there's actually subtypes.

And the subtyping of disease could be very important because there could be different sort of factors in each subtype.

And then you might design a medicine then to go after a specific subtype.

And that's what's been happening here, as I will explain when I come on to that approach to how we treat these things.

So it's complicated enough in a way, but overall, to summarise that bit, it's in the skin, it's red, it's scaly, it's sore.

And then remember, you get this flaking happening because eventually the dead skin falls off the skin.

And that is the flakes you get, these opaque coloured flakes.

That's happening all the time in normal skin, remember.