There are many possible causes of a swollen tongue. A swollen tongue can result from such abnormal processes as infection, inflammation, allergy, genetic disorders, trauma, malignancy and metabolic diseases. Some causes of a swollen tongue are serious, even life-threatening, such as a anaphylactic reaction.lossitis causes a swollen tongue due to a variety of infectious or inflammatory conditions. Infectious conditions include a tongue bacterial infection, yeast infection or viral infection, such as herpes simplex.