Jenny,
Is the rash fungal or is it due to loose, watery stools? What kind of creams are you using? Wipes?
It could be any number of things--
With a casein free diet she may be low on dietary fats, thus causing watery stools that easily irritate her bum. It could be a fungal rash and require nystatin or some other fungal cream. Does she have a white coated tongue? Is her rash a solid red color, or is it a series of tiny red pimples?
Does she have a history of skin conditions? eczema? cradle cap?
The rash may be completely unrelated to being GFCF too. It could be that you have introduced something new into the diet that is not agreeing with her. My youngest always gets rashy when he eats foods with tomatoes in them.
Caryn
P.S. hang in there. This is the hardest part-- changing habits and learning the ropes. You have to be patient and give it a good chance. Healing a gut imbalance is not an overnight thing. It takes a long time. You may not see positive results for up to a month after starting the diet. If there is damage, and chronic digestive problems are definitely a sign that there is, then healing will be slow and gradual. The gluten-free diet is healthy, and it can't hurt Isa, so keep your chin up. Give it at least 30 days. And don't get crazy with gluten free breads and snacks just yet. They have a lot of odd grains in them and may cause more harm than good as you try to navigate this whole process. There will always be time for that later on if you find the new diet has been really beneficial. Give her plenty of fruit, veggies, and plenty of fats: salmon, red meat, avocado, nuts, flax seed, olive oil, a good fish oil supplement like Nordic Naturals (bad ones may have mercury contamination). If she is not big on eating meat, mash the bananas and put a teaspoon of the beneficial fats in it (evening primrose oil, flax, etc....) Be sure to give her a good multivitamin too (and be sure it is gluten and corn free, as a precaution). I have gotten into the habit of making big portions and freezing leftovers to give myself a break in the kitchen. If you don't have the funds for a good allergy/intolerance test right now then keep a food diary for Isa. Over the course of a few weeks you may see some patterns that will point to the possibility of additional allergies/triggers. Be careful with overuse of eggs and corn. There are a lot of parents of kids with tics/TS that have egg and corn sensitivities/allergies. Focus on giving her: blueberries, bananas, potatoes, (potato chips when you are 'desperate"), green beans, peas, apple sauce, yams, zucchini, carrots, chicken, beef, fish, etc... Forget about the snacks. Just offer good solid food choices every three hours, balancing your carbs/protein/fats. You can do this Jenny. I know you can. I've been where you are and I remember the frustration. Heck, I didn't even know how to cook when this all started. I can laugh about it now, but at the time it wasn't funny. Just check the first couple of recipe entries on my blog. They are laughable to me now.
Keep trying... Look at it this way, If it works, you may be looking at a future with no additional treatments required: regular doctor visits, heavy vitamin/mineral treatments (8-10 pills a day), no expensive treatments, daily drugs, regular lab tests, etc... It is a good place to start, especially if you eventually discover it is the only thing that Isa needs.