What Causes Swollen Right Eye,face And Throat?

Hi My friend has a swollen right eye, face and throat. He thinks it may be an allergy to tomato sauce do to the fact that it happened after eating! Although I m curious if it could possibly be something else where it has been a couple days and still very swollen, puffy and red! He has not seen a physician yet! He seems to still be eating and not complaining of pain. Can you get an allergy to food on one side of face?