My 2 year old son has intermittent bilateral bright red ear lobes that are very hot to the touch. should i be concerned?a neighbor suggested htn?

Vasodilation: I do not know of any correlation between bright red ear lobes and hypertension. It sounds like he is having a transient vasodilation involving his ears lobes (blood flow gets increased to this area). If he really has no other symptoms, i would not be too concerned about it at this point.

Not really: Some kids blush this way, and may also do so at random. There is no correlation to a disease or condition I know of.