Mohamed,
I don't know excatly what you mean "does it make a difference"? I'm not sure what kind of Ichthyosis you have, different kinds have different "obstacles". I have EHK,some things can be painful for both partners. I don't just mean sexual activity either, with my ichthyosis I cut very easily so being rubbed on, knelt on, pushed on or even just layed on can peel my skin off. Without being too descriptive I can tell you lubricants help. Other then that the only thing you can do is experiment with your lover as to what hurts and what doesn't, it can be fun! You'll figure it out. Hope this has helped. If you have any specific questions write in private, my email is keithx1@earthlink.net maybe I can help.
Keith.