Angioedema is actually an allergic reaction of the skin. So that particular part of the body could be any part of the body becomes reddish, swollen and painful. It can be sometimes itchy also. We need to identify what you are allergic to. It could be food, drugs, dust etc. Identify what is the triggering factor and avoidance of that factor will cure angioedema, plus antihistamines. The combination of sedatives and non-sedative antihistamines will cure angioedema. If it is really severe then you need to take oral steroids also. I don’t think flax seed oil has any role in angioedema.
source