Rules for anaphylactic shock/general allergies?

[PalladiumBrony]

Has anyone found, or made up, any house rules for anaphylactic shock/severe allergic reactions? Dead Reign: Dark Places makes a passing reference to it under its section on bed-bug bites (p. 16), but only so far as to give some flavour text on the symptoms (your blood-pressure and cardiovascular function absolutely tank, and you go into shock, and it causes "swelling", which it doesn't mention but we know IRL can cause your throat to swell up and this can lead to suffocation) and that it's very rare (2% chance) for someone to have this kind of allergic reaction to bed bugs specifically.

Further to this, has anyone got any rules for more mild allergies? Ones with symptoms like sneezing, watery eyes, hives/itching/rash, or non-fatal swelling - I know of people who are allergic to, for example, seafood to the point where if they eat it, they swell up like a balloon and turn a rather alarming colour, but it's generally not fatal for them.