Hives, perhaps?

It ain't shingles

I am with Angela, Mike and Art on this one. Food allergy, laundry soap, bugs, something

My younger boy gets it when he over heats from running out in the play yard and starts to scratch. Once he starts, there's no going back the rash / bumps get worst and more itchy. Ususlly around his butt cheeks or behind his knee where sweat can be the cause of it. A warm shower and some Benadry then he's good to go after 15 minutes if he doesn't scratch it again.

Maybe scabies??? Do they itch more at night?

Your description is typical, almost pahtognomonic, to urticarial reactions. They are one of the most common skin reactions and, at least with children, mostly associated with infections, particularly viral. In it self completely harmless but the itch is bad sometimes. An allergy will sometimes go with urticarial skin reaction too, but usually with other organ symptoms too. An airborne allergy, hence, will primarily create symptoms from the upper airways, like nose and eyes. A food related allergy from the mouth to the bowel.
If you have access to any antihistamines (loratadin, cetirizin etc) - try 1-2 tablets daily. It will most of the time ease the itch.
Of course go see a doc too. I only know about kids. :)

Well I certainly wouldn't argue with "that" bit of wisdom :D

'cause I have no idea what Markus just said :p

That is because he spelled pathognomonic wrong.

I don't think it's from laundry soap, but I learned about 20 years ago to pay attention to how those things affect you. I got a small sample packet of a new laundry detergent deposited on my door step or in my mail box. I thought it was just about right to wash my undies in, so I threw them in the washer along with the laundry sample. After I used most of my others up, I started mostly using those I had laundered with the sample. I started having the skin on my unit & sack turn reddish purple and start to slough off. I'd washed a lot of underwear so this went on for quite a while, and I finally went to the doc. He couldn't locate any reason, so I lived with it in mystery until it finally went away. Much later on I realized it coincided pretty much with that laundry sample. If a laundry detergent can affect somebody that way, I'm sure some can cause other types of reactions.

I've been pretty clear so far since 7am. [knock on wood]

I'm seeing a dermatologist tomorrow morning.

Take some good pics if you get any more bumps, tough to diagnose something if it is not there.