My daughter Nina is 1 and has EHK. On the advice of our specialist nurse and consultant, we applied for Disability Living Allowance for Nina, and having been turned down initially, got awarded the highest rate on reconsideration. We have just renewed the claim, so hopefully we will continue to get DLA.
I also get Carers' Allowance as I'm not working at the moment; I think you're eligible if you get middle or higher rate DLA.
The DLA forms are a bit of a nightmare, and like you, I don't consider Nina to have a disability. However, if that's the language I have to use to access financial support to which we are entitled, then so be it. It felt quite upsetting to fill in the forms on the basis of a worst case scenario, but that is what we were advised to do. Also, we were told to pretty much expect to be refused in the first instance, but to keep at it!
What sort of Ichthyosis does your child have?
Anyway, hope this is of some help. Oh, another thing I just thought of; there's a section on the form for a professional involved in your child's care to fill in. My advice would be to make sure someone (consultant, social worker, nurse, whoever you think best) completes that, even though it says it's optional, as we didn't first time round, and I suspect they automatically knock back any claims that haven't got professional support in that section. Just my suspicious mind!