What Causes Dizziness While Suffering From Asthma?

My son is 24 years old and in excellent physical condition. He has suffered from asthma most of his life and uses an inhaler. In the past year he has had three episodes where he has become very dizzy, he said it is like being very stoned (he doesn t smoke marijuana) his vision becomes tunnel like and he starts feeling a numbness in his arms and a tingling up his neck and around his head. Today he past out during one of these episodes. We took him to the ER where they could find nothing wrong with him. I am wondering if this could be a type of migraine or a severe panic attack. He does suffer from panic attacks and I know I have a few that caused me to become faint.