Swollen lips may be a localized allergic reaction, or it may be the harbinger of acute lipitis, local trauma and other diseases. 1. Allergic reaction: lips are composed of loose connective tissue, if you eat food that is easy to cause allergies, there will be lip angioneurotic edema phenomenon, and lip swelling symptoms are obvious. 2. Acute lipitis: mostly due to trauma, smoking, poor oral hygiene, etc., so that the mouth is subjected to long-term stimulation, can lead to lip swelling, can also be accompanied by swelling, congestion, flaking and other uncomfortable symptoms. 3. Local trauma: local trauma, resulting in a local inflammatory reaction, and then the situation of swollen lips. Lip swelling is also considered to be caused by other factors, should be as early as possible to the relevant examination to clarify the cause of the disease, and under the guidance of the doctor to deal with the correct.