What are the common causes of upper lip swelling?

Common Causes of Upper Lip Swelling

Upper lip swelling most commonly results from allergic reactions (particularly IgE-mediated angioedema from foods, medications, or insect stings), infectious/inflammatory processes, dental pathology, or less commonly from granulomatous diseases or structural lesions.

Allergic and Immunologic Causes

Allergic angioedema is the most frequent acute cause of lip swelling, typically presenting as part of a type I hypersensitivity reaction. 1, 2

• IgE-mediated angioedema occurs from exposure to foods (especially eggs, shellfish, nuts), medications, or insect stings (bee/wasp venom), and represents acute subcutaneous edema with improperly restricted swelling. 2
• Approximately 50% of patients with angioedema also develop urticaria, which strongly suggests an IgE-mediated allergic reaction. 1, 2
• Facial or lip swelling combined with urticarial rash or bronchospasm strongly indicates an IgE-mediated reaction requiring immediate treatment. 1
• The main life-threatening risk is progression to tongue, laryngeal, and tracheal swelling causing airway obstruction. 2

Immediate Management of Allergic Lip Swelling

• Epinephrine is the drug of choice when angioedema threatens airway compromise. 1, 2
• Initial treatment includes antihistamines and glucocorticoids for most forms of angioedema without airway involvement. 2
• Early recognition of potential airway difficulty (hoarseness, lingual edema, stridor, oropharyngeal swelling) is paramount, with planning for advanced airway management including surgical airway. 1

Infectious and Inflammatory Causes

Granulomatous cheilitis presents as recurrent or persistent lip swelling and represents a rare but important differential diagnosis. 3

• Characterized by recurrent labial tissue swelling that may progress to permanent enlargement, most frequently affecting the lower lip but can involve the upper lip. 3
• Histologically shows scattered aggregates of non-caseating granulomas. 3
• Represents the most frequent sign of orofacial granulomatosis, which encompasses sarcoidosis, Crohn's disease, atypical tuberculosis, and Melkersson-Rosenthal syndrome. 3
• Treatment with intralesional or oral corticosteroids is typically successful. 3

Dental and Structural Causes

Dentigerous cysts with mesiodens can cause slow-growing, painless upper lip swelling, though this is rare (0.15-1.9% prevalence). 4, 5

• Present as soft intraoral swelling on the labial surface of the maxillary incisor region with corresponding extraoral upper lip swelling. 4
• Radiographic examination demonstrates radiolucent areas with supernumerary teeth extending to adjacent tooth roots. 4, 5
• Treatment requires surgical enucleation of the cyst and extraction of the mesiodens. 4

Trauma-related swelling from displaced or dilacerated teeth can cause recurrent upper lip swelling. 6

• Mechanical trauma from dental appliances, fractured teeth, or abnormally positioned teeth should be evaluated. 1, 6
• Requires combined surgical, endodontic, and orthodontic management. 6

Critical Diagnostic Approach

For persistent or recurrent lip swelling without clear allergic trigger, systematic evaluation is essential:

• Determine potential allergen exposure through detailed history; perform skin prick testing if allergic etiology suspected. 2
• Any swelling persisting beyond 2 weeks requires specialist referral and comprehensive workup including biopsy. 7, 8
• Radiographic imaging is indicated when dental pathology is suspected. 4, 5
• Histopathologic examination is essential to differentiate between granulomatous diseases, malignancy, and other causes. 3

Key Clinical Pitfalls to Avoid

• Never delay epinephrine administration when angioedema involves the airway—fatal reactions are associated with delayed epinephrine treatment. 1
• Do not assume benign etiology without proper workup for persistent swelling, as serious systemic diseases (Crohn's disease, sarcoidosis) can present with isolated lip involvement. 3
• Inadequate biopsy may miss granulomatous features or early malignancy in chronic cases. 7
• Overlooking dental causes delays appropriate surgical management and allows progression of cystic lesions. 4, 5