Allergic reaction? Or heat rash? Help!

Mandy • Mommy of 2 wonderful boys 5.18.17 💙 4.3.19 🌈💙

When I got home from work my husband was changing my 2 year olds diaper and I noticed a few red blotches. I lifted his shirt and it was everywhere. What could this be? He didn't eat anything today he hasn't normally.