I don't know what causes it or what sets off a flare, except maybe stress, but in my non-scientific mind, the "problem" is that the bladder is unable to hold any urine without pain...that's why the bladder constantly needs emptying.  My theory--along with that of a few others--is that the mucosal linig of the bladder has eroded or thinned or something and the underlayer, unprotected against urine, objects.  I take the stuff that makes you pee orange (Azo standard) and Urispas (to break the cycle of pain spasms) and, when needed but I don't usually need it because I can get in there early when I feel it starting, something for pain.  But even now, after learning how to deal with it, I have occasional lost weekends or lost Tuesdays, curled up in a fetal position loaded on something to make it all go away.  (And part of that problem is you can't get REALLY loaded on pain stuff because you have to be able to get back and forth to the toilet.  lol)

I can tell you that for YEARS most IC patients are misdiagnosed with a UTI.

Could be any of the causes you mentioned...

Mayo Clinic says:

Causes

By Mayo Clinic staff

Interstitial cystitis

Your bladder is a hollow, muscular, balloon-shaped organ that stores urine until you're ready to empty it. In adults, the bladder expands until it's full and then signals the brain that it's time to urinate, by communicating through the pelvic nerves. This creates the urge to urinate in most people. With interstitial cystitis, these signals somehow get mixed up, and you feel the need to urinate more often and with smaller volumes of urine than most people.

It's likely that many people with interstitial cystitis also have a defect in the protective lining (epithelium) of their bladder. A leak in the epithelium, for example, may allow toxic substances in urine to irritate your bladder wall.

Suggested but unproven factors that may contribute to interstitial cystitis include an autoimmune reaction, heredity, infection or allergy.

The feds say:
www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001508/

 Thank you, this really caught my attention, as my daughter has had "issues" since she was very little.  I'm going to keep this in the back of my mind when looking for an answer for her.  This just sucks!

Oh my hell!  I can't hug you hard enough or long enough!  I wonder if a Foley catheter might be in order, just until you get past the worst of your recovery and/or flare?  I know it's not ideal, but Jeeze Louise!  You need a break!  Best wishes and deep sympathy!

Congratulations on your DS!

I hope your IC flare up resolves quickly, poor thing.

Sending best wishes for great success with both!

Dear Anonymous,

Well if you are special to Sue then that can only mean you're an amazing person. I really am sorry that you are suffering from this **** and I'm sure it sucks. I've talked with Sue on the phone when she is going through a flair and she sounds exhausted, so I'm sure you must be too.

Chronic pee pain and no sleep deserves a  Hershey's chocolate bar w/almonds, and you need to wake someones ass up so they can go buy you some chocolate. It works...TRUST ME

Please hang in there and know that there are people here who care about you.

Love

I logged on here for the first time in a few weeks and this made my day!!  I don't mind people knowing I have this horrible bladder disease.  Oh yes, stress makes it worse and I have had three people close die this month so that made my flare worse!! I do notice certain foods and drinks make it a lot worse too! They may not for everyone, but I can tell shortly after some things!  Chocolate is a bladder irritant and I only like the chocolate protein so I am not liking my unflavored protein in milk etc.  Thanks for the hugs!  Oh, I do even think of wanting a cath, but they hurt my bladder soooo much!  I do actually have numbing meds to put in my bladder with a child size cath, but it only seems to help for 45 minutes.  I am doing a little better. I always am uncomfy and have to go, but I am not crying, rolling around in bed in pain like I was!!!  It has made eating and drinking a lot harder because I am one that can eat a food that has acid in it and feel it in the worst way a little while after that!  The scary thing is that vitamin C and multi vits can really trigger some people's pain.  I stopped my extra C for now, but get it in my multi plus tons of other vits.