Spontaneous (ie, nontraumatic) lip swelling is usually painless. Itching may or may not be present. Cheilitis sometimes causes lip swelling, but patients typically present because of the painful inflammation and lesions.
By itself, lip swelling is not dangerous. However, when lip swelling is caused by angioedema, concurrent swelling in the oropharynx and/or lower airways can be fatal.
Lip swelling may be acute or chronic.
Acute lip swelling may be caused by
Allergic reactions (eg, to foods, medications, illicit drugs or substances, lipstick, airborne irritants, nickel)
Environmental factors (eg, cold and dry weather, sunburn)
Nonallergic medication causes (eg, angiotensin-converting enzyme [ACE] inhibitors, calcium channel blockers, certain fibrinolytic agents)
Chronic lip swelling may occur with
Acromegaly (often with coarsened facial features and/or enlarged tongue)
Hypothyroidism (often with facial puffiness and/or enlarged tongue)
Rare causes of chronic lip swelling include ongoing exposure to an unsuspected allergen, cheilitis granulomatosa, and Crohn disease.
The first step in evaluation is to assess airway patency and establish and control the airway if necessary. Diagnostic inquiry focuses on potential causative exposures and underlying diseases.
