The feeling you get after loads of hours on LAN parties. You feel cold even though you are sweating and hot. This is most likely caused by either all the bad food you've eaten, all the energy drinks or just staying up for a while.
After 24 hours of LAN'ing:
John: Damn, maybe I've caught the flu! I'm feeling so cold even though I'm hot and sweating.
Peter: Mate, you've got the LAN-cold.
After being off of work or school for being sick you return to a huge pile of work waiting for you causing you to stress and work late nights, which leads to an echo cold.
Can be used to refer to a cold caused by an earlier sickness for any reason.