We tell people (family and close friends that inquire) that our son has an adrenal insufficiency.  If they ask for more detail, we explain that his body cannot produce Cortisol and Aldosterone, and that these two substances must be replaced for him by taking tablets.  We also say that he requires a little more watching in cases of illness, stress, and the heat, but is otherwise just an average kid.  We don’t fell compelled to tell everyone in the world about his condition, only family and genuinely concerned friends.  On the occasions when a nosy stranger or even a co-worker who has never said two words to me before has asked about his Medic Alert bracelet, I give them the "adrenal insufficiency" answer.  If they press the issue, I give them the Raised Eyebrow Stare of Death and in my most snooty tone, I say "We don’t discuss our son’s medical history with strangers."  It’s quite entertaining to watch them scurry away in shame, believe me (LOL)!

Best of luck with your little one.  Just remember that you only have to provide this info to those responsible for his safety, and only to the degree that he, you, and your husband are comfortable.