My father, uncle and cousin get cold sore when they sleep in a draft or breeze. What would cause this?

Good question. Apply the "three interlocking circles of health" genetics (1st circle) is always a feature of health and disease. It interlocks witrh "stress", (2nd circle) in this case the sensory input from the draft. The third circle is the only one that counts (other than avoiding the draft---- the stressor) nutrition! nutrition supplies the energy for meeting the "stress" . Try a supplement of lysine.