Psoriasis is thought to be an immune system problem. Triggers include infections, stress and cold.
The most common symptom is a rash on the skin, but sometimes the rash involves the nails or joints.
Treatment aims to remove scales and stop skin cells from growing so quickly. Topical ointments, light therapy and medication can offer relief.
When I worked in psychiatry I’ve seen psoriasis can have a link with depression and I’ve seen people who had it over their whole body. But hard to determine what comes first. We’ve had clients who’s psoriasis increased when they were depressed, but I can imagine you get depressed when you have severe psoriasis too.

A process of elimination could help. Remove things, maybe your laundry products or a certain food group, see how he responds. If no change, try removing other things, one at a time. Isn’t cirrhosis a liver problem, completely different to psoriasis?

yes physiogel from the chemist is great for this as well. $17 a bottle i’m pretty sure at most places

Using hypo allergenic cleansing products, in the laundry and to clean himself, is beneficial. A change in diet can help too. Some cases are made worse by things that are eaten. Do a thorough Google search for more helpful advice

My brother in law has psoriasis, he uses prescribed steroid cream but also qv bath wash, he has to avoid soap and certain shampoos also. If he stops taking the steroids it can flare up really badly

I’ve had Psoriasis since I was little, luckily for me not too bad, though I do know of many others that do and most of them swear by coconut oil. Tea Tree oil is supposed to be good. Steroid creams helps but are only safe for short term use. Light Therapy has been known to help some people too. If it gets severe enough there are what’s called Biologic’s that can work really well. I hope this helps.