What causes sores on the lips and swollen gums?

Causes of Sores on Lips and Swollen Gums

Sores on the lips and swollen gums have multiple potential causes, ranging from common infectious conditions (herpes simplex virus, candidiasis, bacterial infections) to inflammatory disorders (aphthous ulcers, pemphigus vulgaris, Stevens-Johnson syndrome), traumatic injury, and allergic reactions.

Common Infectious Causes

Herpes Simplex Virus (Cold Sores)

• Herpes simplex labialis presents as painful vesicular eruptions on the lips that form unsightly crusts, causing cosmetic disfigurement and psychosocial distress 1
• Cold sores typically occur on the lips and perioral skin, distinguishing them from canker sores which occur inside the mouth 2
• These lesions are common in young, otherwise healthy persons but may indicate immunodeficiency when severe or chronic 3

Candidiasis (Fungal Infection)

• Candida infection can affect the lips (angular cheilitis) and oral mucosa, causing inflammation and discomfort 4
• Chronic oral candidiasis in otherwise healthy patients should prompt evaluation for immunodeficiency states 3
• The condition responds to antifungal therapy with nystatin oral suspension (100,000 units four times daily for 1 week) or miconazole 5, 4

Bacterial Infections

• Bacterial colonization of oral mucosa and lips can cause inflammation and swelling 5
• Acute necrotizing ulcerative gingivitis represents one cause of rapid-onset oral ulcers and gingival inflammation 2
• Treatment requires antiseptic oral rinses such as 0.2% chlorhexidine digluconate mouthwash twice daily 5, 6

Inflammatory and Autoimmune Causes

Aphthous Ulcers (Canker Sores)

• Recurrent aphthous ulceration presents with well-demarcated ulcers having a yellow/white base with an erythematous border 7
• These lesions occur inside the mouth on the buccal mucosa, tongue, and soft palate, not on the lips themselves 2
• Canker sores are common, relatively banal diseases occurring most often in young persons 3

Pemphigus Vulgaris

• Oral lesions in pemphigus vulgaris are characterized by painful ulceration involving any surface of the oral cavity, with the buccal mucosa, soft palate, lips and tongue most frequently affected 5
• Painful erosions on the gingival margins may inhibit tooth brushing, resulting in plaque accumulation that compounds pain and inflammation 5
• Patients with pemphigus vulgaris have worse periodontal status than matched controls 5

Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis

• Oral involvement is characterized by painful mucosal erythema with subsequent blistering and ulceration 5
• Similar involvement of the vermillion of the lips progresses to hemorrhagic sloughing with development of dark adherent crusts 5
• The tongue and palate are frequently affected, and drinking and eating are usually severely compromised 5

Erythema Multiforme

• This condition represents one of the common causes of rapid-onset oral ulcers 2
• It may present with multiple oral ulcers and lip involvement 2

Traumatic Causes

• Traumatic ulceration is often related to local trauma from sharp food, dental appliances, or iatrogenic causes 7
• Innocent solitary ulcerations from trauma must be distinguished from malignancies 2
• Mechanical factors such as ill-fitting dentures or loss of vertical dimension can contribute to lip and gum problems 4

Allergic Causes

• Allergies represent one of the common causes of rapid-onset oral ulcers 2
• Contact with irritants such as over-the-counter anti-acne medications, solvents, or disinfectants can cause lip irritation 6
• Allergy to local anesthetics such as benzocaine should be considered when evaluating lip and mouth irritation 8

Less Common Causes

Orofacial Granulomatosis

• This rare disorder affects the orofacial region and is clinically characterized by diffuse, nontender, soft to firm, painless swelling restricted to one or both lips and intraoral sites such as gingiva 9
• Early diagnosis is essential for better prognosis, as delay results in indurated and permanent swelling 9

Systemic Conditions

• Multiple chronic oral ulcers may be associated with disturbances of the immune system, including erosive lichen planus, mucous membrane pemphigoid, and pemphigus vulgaris 2
• Diabetes or immunosuppression should be evaluated as potential underlying causes 4
• Blood disorders may present with persistent oral ulceration 7

Critical Diagnostic Considerations

• When ulcers persist beyond 2 weeks despite treatment, biopsy is indicated to rule out squamous cell carcinoma 7
• Constitutional signs and symptoms, along with lesions on skin and/or other mucosa, are most useful in identifying the cause of oral ulcers 2
• Full blood count should be considered for persistent ulcers to rule out blood disorders 7
• Bacterial and fungal cultures should be obtained when infection is suspected 5, 6

Important Clinical Pitfalls

• Misdiagnosing a single ulcer as aphthous when it could be early herpangina or another condition 7
• Overlooking systemic conditions that may present with oral ulceration 7
• Failing to distinguish between herpes simplex (on lips) and aphthous ulcers (inside mouth) based on location 2
• Not recognizing that severe or chronic presentations in otherwise healthy patients may indicate immunodeficiency 3