I have EHK and am 32/male, I have been taking anti biotics basically permanently my whole adult life and have not had any ill effects. I am currently on about 500mg cloxicillian per day which maintains my infection rate quite well. I still get the odd minor infection from time to time and sometimes I need to take abit more, but I have been fortunate at this point to not have become resistant to the anti biotics. Since it sounds like it has become a fairly reoccurring issue for your son, I think a regular systematic anti biotic "maintenance" set up is probably what your going to find that works best for Evan. I don't get infections alot, but I prefer the everyday or every other day maintenance to the risks of infections. I also noticed quite immediately (within 2 or 3 days) if I don't take the anti biotics that I tend to develop infections. In other words, I pretty much need to stay on the anti biotics level that I am taking. As you've probably come to realize, not all Ich people have the exact same symptoms and infections etc, so what works for one person might not work for others, but that is my experience thus far.