DS2 is battling the same issue.  We went through this last summer at this time - I just finished paying off the ER bill.  That trip involved hives that kept coming and bathing and Benadryl wasn't stopping them. 

The most recent bout started all over his chest on Tuesday and have not gone away.  He doesn't seem itchy and frankly I haven't medicated him because it doesn't seem to help.  No other "allergy issues" that would point to something ingested or inhaled and no illness on the horizon.  He has since been in the bath (no new products, in fact one bath was sans products), been keeping cool, has been in the pool a few times, no detergent. 

Our allergist tested him for cold water uticaria with no luck.  Initially I thought it might have been the flea powder (one room was infested but it was closed off and DS only walked by it) or spray from the hose.  And then I have just decided to say it's this time of year and there is little control over it.

Any recent illnesses?  Viral hives, perhaps?

What's pollinating where you are?

Quote from: starlight on June 25, 2012, 08:30:37 PM
How warm are you around the time the hives pop up? Sweaty at all? Are the areas always covered by clothing?

I don't think they're necessarily heat-related - I've been breaking out no matter what temperature I'm at (although I have noticed that they do get worse with heat). The areas aren't always covered by clothing, so I don't think it's necessarily related to laundry detergent or anything.

How warm are you around the time the hives pop up? Sweaty at all? Are the areas always covered by clothing?

I've been getting hives all over, on and off, for the last week and a half and it's driving me crazy right now. I woke up one morning with a few hives on my back and stomach, then they went away on their own a few hours later - only to come back a bit later in the day, this time all over my back, neck, and arms. This pattern has continued for the last nearly-two weeks - I keep breaking out in hives randomly, they'll go away, then come back within a few hours. Sometimes it's just a few hives here and there, sometimes it's hives everywhere. I do know that hives are often idiopathic, and I have gotten them for no apparent reason before, but I was wondering if anyone had any input.

An extra dose of Zyrtec has been helping kick them back a bit, but it seems like everything itches right now.