Mk13, you might want to look at the inactive ingredients too - our dd who has food allergies had the same type of reaction on singular, when she was around 4-5 years old, and the culprit wasn't the singular,MIT was something. In the inactive ingredients. She's also our sensory-challenged kid and some of what looked sensory was related to allergies.

I'm so glad you found the trigger - and I hope you're able t find someg else for his asthma.

Best wishes,
polarbear