What should you know about slightly swollen lips?

Mild lip swelling may follow a new food, medicine, cosmetic product, dental product, insect bite, irritation, infection, or injury. [Angioedema](/conditions/angioedema/) is a deeper swelling reaction that can affect the lips, face, tongue, or throat; it may occur with hives but can also occur without them. The timing, whether one or both lips are affected, pain or itch, and any new exposure help a clinician assess the cause.

Stop using a newly introduced lip or face product and avoid the suspected trigger until you have advice. Note when the swelling started, what you ate or took, and whether it is changing. A cool compress may provide comfort. Do not take a medicine that has caused a previous reaction, and do not rely on home observation if symptoms are progressing.

Call emergency services immediately for trouble breathing, wheezing, throat tightness, difficulty swallowing, a swollen tongue, dizziness, faintness, or rapidly increasing swelling. Seek prompt medical assessment for fever, severe pain, spreading redness, pus, or swelling after a new medicine. Even mild swelling should be discussed with a clinician if it keeps returning or has no clear trigger.

Could this be an allergic or irritant reaction? What exposures should I avoid? Do I need an emergency plan for recurrence? Which symptoms mean I should call emergency services? Should medicines or dental products be reviewed?