Pemphigus Foliaceous

My 1 year old female cat has been diagnosed with pemphigus Foliaceous a week ago (4th July 2023) she has been put on high dose steroids and has a follow up vet appointment in 2 days time, I'm not seeing any improvement after 5 days, how long does it take for the steroids to work, also for the last week my cats fur is soaked wet through as if she has just been in a rain storm! Is this normal for this condition? I've read all I can possibly find on this condition but can't find this, she's eating and drinking alot of water but as only urinated twice in 5 days, I'm so worried about her

Hello - a quick reminder of the ground-rules first:  your vet knows much more about your cats' case than I do.  I can make general comments about various diseases to provide you with some background, but when it comes to your cat, your vet will be much better versed.  It sounds as though you are concerned about her in the immediate term and for that, your vet ought to have some emergency provision in order that any unexpected signs or symptoms can be run past them and assessed.  However, I will make some general comments about Pemphigus.

Pemphigus is a disease of the immune system, an auto-immune disease.  You may have heard that diabetes in people is caused by the human immune system attacking the body's own cells.  Well, pemphigus is an example of a different auto-immune disease, in cats; the body's immune system tries to attack its own proteins.  In the case of pemphigus, it specifically targets 'Desmosomes,' those protein units holding the skin-cells together in a nice, continuous film.  Once these proteins have been disturbed, blisters tend to form.  These can often rupture and manifest as a sticky crust on the skin.  They are a symptom of Pemphigus.

If this is what you are seeing (you vet will have to confirm it or otherwise), it sounds as though it is normal for the condition.  Because desmosomes would have still been attacked by the immune system the morning of the day the treatment started, it may take a while for the effect of taking the steroids to filter through the system - my understanding is that it can be a few weeks before remission is achieved.

Increased thirst can indeed be a side effect of steroids.  This is worth speaking to your vet about as there are also other possible causes.  It may be that your vet is able to lower the dose once the drugs have started to be effective, in order to try to find the lowest useful dose.  However, for your cats' comfort, they will likely want the symptoms to be in remission first.  For other inflammatory conditions, there are now various steroid alternatives on the market but I haven't heard of them being used for Pemphigus - perhaps that is something your vet could research or, indeed, may have done so already.  Mostly, treatment for Pemphigus tends to be very successful in cats, so we wish you all the best.