my 7 year old son has started breaking out with a funny rash sinc...

I have actually had a similar rash, the first time I saw it (sometimes I get it on my neck, and sometimes my arm) i was pretty scared that it was something nasty, then it went away with a little benadryl cream, so i just put it down to direct contact with pollen (there is a fruitless mulberry tree in the yard where my dogs play, and despite washing them with a towel when they come in, i know there is still some on them) I never considered it as a side effect, but it has only been happening the past couple of years (I am 36 and had allergies all my life, ) and I have been with zyrtec during that time. huh