Hi there. Thank you for your question. I will be helping you out with your queries
Has he been seen for this as yet?
Any tests done?
Any other medical problems?
On any medications?
You should definitely take him to a doctor.
Allergies is the first thing that I would rule out.
Antiallergic medications may help him with the symptoms that you are mentioning.
If there had been issues with lactose problems or lactose intolerance that would usually cause a diarrhea more than anything else.
Yes blood tests like IgE levels and looking at the eosinophil levels can help us in knowing if a person is having allergies.
There are other tests like skin patch testing that can help determine whether a person has allergy or not.
No it is not a fasting test
It can be done there and then.