Swollen lips may be caused by allergic reactions, injuries, chapping or sunburn, infections, and cysts called mucoceles. The swelling comes from either inflammation or built-up fluid under the skin.

Allergic contact cheilitis (ACC) is allergic contact dermatitis (ACD) affecting lips. It causes swelling, inflammation, and possibly scaly skin. The term “cheilitis” refers to short- or long-term ...