First Kiss". While the kids are in their early teens, this is a process that I go through every single time I meet someone new.
So, when should you bring it up? Honestly, I'd rather not and in the past I've underplayed my allergies to the point of not mentioning them until I'm being fed oxygen by some really buff firefighters. So, I've realized that's not the best way to go about it and I try to be honest with people.
With the whole dating experience, it isn't the first thing I bring up. I've never had a meal with a guy I just met; so, I figure I'm allowed to decide if I like him before sharing. However, before a meal occurs, I do have a discussion. I let them know that I have severe food allergies, but I don't go into detail unless they ask, which they usually do. At this point, I let them know that they don't have to worry, but any nice girl or guy will. I let them know I have a MedicAlert bracelet which lists my allergies, an EpiPen/Twinject which I know how to use and an easily-accessible makeup bag with medications. I don't ask them to become familiar with using my EpiPen/Twinject unless the relationship progresses. I have the luxury of doing so due to the nature of my reactions. If you don't have the luxury, this might be part of your discussion. It might weed out the jerks too.
Don't be afraid of recommending or vetoing a restaurant (in the nicest way possible). First dates are not times to have reactions. Sure, they might happen, but you have every right to minimize the possibility. That said, I've made my fair share of concessions over the years and ended up eating my fair share of green salads and french fries.
I've also had to have the "kissing" discussion. Past boyfriends may have just had a coffee with milk before coming over and a simple kiss at the door results in hives all over my face. So, brushing teeth after that coffee and waiting at least a half hour before kissing becomes the norm. And sometimes, if the situation doesn't allow it, we just don't kiss. To the credit of the guys I've dated, I've never suggested the brushing thing. They've done that by themselves.
As for the eczema and asthma, those are conversations which I leave until the relationship is going somewhere. I've never met a guy who was turned off by either. I've been involved with a couple of amazing guys who could have cared less. Still, especially with eczema, the proof is visible but it's still personal and I think it's fair to keep that to yourself until you decide you're ready.
I don't date guys who smoke (I'm very anti-smoking anyway) or guys with pets since I'm far too allergic to pet dander/fur/whatever. I've told past boyfriends that if they've been around pets that I can't go near them since it can result in skin breakouts and asthma attacks. So, same as the brushing, they change their clothes before coming to see me.
I don't over think this. I tell them when I tell them. Usually if we're going out to eat. If they ask questions, I answer. When I trust them, I'll show them my kit. In the past, I've heard some stupid, insensitive jokes and I've let them go. Now, I have no problem letting people know what's appropriate and what's not. Most friends don't purposely try to hurt other friends and it's up to you to let them know when they're crossing a line, especially when it's unintentional. People often use humour when they're uncomfortable or unsure of what to do or say.
When I was younger, kids were a lot more vocal and cruel about the visible signs of my eczema. Since I've gotten older the comments are usually absent or at least voiced out of concern. Same thing goes with romantic relationships though - I don't discuss it unless I want to. It simply doesn't define me.
Employers are trickier than the rest. Once you're hired (and not a moment before), speak confidentially with the HR manager. To be cautious, it's best to document all interactions you have regarding this issue. While the majority of employers are accommodating, be wary of those who do not want to get involved.
employment standards are very specific and you can seek government compensation for days missed due to reactions from chemical exposure. Cleaning solvents, improperly ventilated shafts and insecticides are big deals when you have asthma and you shouldn't have to suffer or lose days of work (and pay) for your employer's misdeeds. Speak up. It's not an easy thing to do, but unfortunately employers need to realize that they can do real damage by being casually negligent.
The messages here are that it's your body and you need to feel comfortable disclosing information in a safe fashion. However, don't be afraid. Don't feel like you're inconveniencing someone. It's your life and your well-being that are at stake. I've had to remind myself of that a lot of times over the years and still do.