What Causes a Swollen Tongue on One Side?

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A swollen or partially swollen tongue can be caused by an allergic reaction to food or medications; bacterial infections; viral infections such as oral herpes; systemic iron deficiency; or exposure to irritants such as spicy foods and alcohol, according to Healthline. Other causes include dry mouth, burns and cuts.

A swollen tongue typically affects the whole organ, but in some cases, the swelling may present only on the back or sides of the tongue, notes MedicineNet. The swelling is referred to as angioedema if it is caused by an allergic reaction to oral medication or food. However, when the cause of the swelling is linked to an inflammation of the tongue, it is known as glossitis.

Angioedema typically occurs rapidly and presents with symptoms including a swollen tongue or throat and, in extreme cases, acute respiratory distress requiring immediate medical intervention, reports MedlinePlus. Glossitis, on the other hand, can develop more slowly, over the course of a day or two, and is characterized by inflammation or swelling of the tongue, discoloration, pain, and smoothness of the tongue caused by the erosion of surface papillae, reports Healthline. Swelling of the tongue may also be caused by oral fungal infections such as oral lichen planus or a yeast infection known as thrush, notes Healthline.

The form of treatment used to cure swollen tongue depends on the cause of the inflammation. Treatment options include antibiotics, anti-fungal medications and vitamin supplements, as well as dietary and lifestyle changes.