"Mysterious Skin Malady #3" [enter stage right]

Last night, after dutifully applying more Elimite than a Wal-Mart (TM) probably vends in a given month, I was finishing slathering Jamie's back when, LO, I spy (actually register via tactile sense first...EW!) a new, improved rash!

Thousands (i.e., far too many to count) of red bumps from his shoulders to his hips. Yes, they blanch. Yes, they're raised. No, there's no streaking. Nope, they're not hives. No, they don't hurt. Yes, they feel "warmish-like" (thank you, Master of Specificity). No, they aren't itchy. No, they do not resemble the afore-treated "scabies" discrete spots or the blistery face/ear deal. Not located on chest, legs, forearms, face, etc. No, when Hydrocortisone cream applied, no change in the trial zone. Yes, he's up-to-date on all immunizations.

As an added degree of difficulty, our internet went down -- effectively isolating me from consulting webmd or other internet-located hysterical web sites. Forced to turn to my trusty tome, Portable Pediatrician for Parents. After determining that he would not expire by morning, I instructed him to strip off his t-shirt and lie on his tummy (back to the air). Within an hour, the red bumps were merely pink and, by this morning, they are far less angrily flared.

Prickly heat? (It was bloody hot yesterday, after all).
A miniscule amount of bleach leftover on his t-shirt? (See you fellow MOTY-wanna-be's, letting one's child have stained clothing is okay).
A localized reaction to the Elimite? (Seems doubtful, considering that the cream was applied almost universally and was well-tolerated a week ago).
Some other source for contact dermititis? (That's always my preferred diagnosis, since it ascribes no fault on my part and little reason to go to the pediatrician).

Or might this be the onset of another PLAGUE??