Allergies are a result of an over-eager immune system.
Allergies in a Campaign Allergies can make great disadvantages for game systems which use them and can be very effective tools even in other RPGs. Characters with allergies may find it difficult to travel to various exotic locales with their companions. Most game systems which describe allergies as disadvantages do not give detailed information about the symptoms of allergies. Keep in mind that some allergies are so severe that they can result in death. A large number of food allergies are like this, mostly because the toxin is completely absorbed into the bloodstream after digestion.