Differential Diagnosis for Swelling of the Cheek and Lip to the Nose with a Negative CT Scan

• Single Most Likely Diagnosis
  • Allergic reaction: This is a common cause of swelling in the face, including the cheek and lip area, and can be triggered by various allergens such as insect bites, food, or substances that come into contact with the skin. A negative CT scan would not rule out an allergic reaction, as it is primarily diagnosed clinically and through history.
• Other Likely Diagnoses
  • Dental infection or abscess: Although a CT scan might show some signs of infection, early or small infections might not be visible. Dental infections can cause swelling in the cheek and lip area, especially if the infection is located in the upper teeth.
  • Soft tissue injury or trauma: Trauma to the face can cause swelling, and if the CT scan is focused on ruling out more serious conditions like fractures or internal injuries, soft tissue swelling might not be fully evaluated.
  • Insect bite or sting: Similar to an allergic reaction, an insect bite or sting can cause localized swelling and might not be visible on a CT scan unless there's a significant reaction.
• Do Not Miss Diagnoses
  • Angioedema: This is a potentially life-threatening condition that can cause rapid swelling of the face, lips, tongue, and throat. It might not be evident on a CT scan, especially if the scan is not specifically looking for it, and requires immediate medical attention.
  • Cellulitis: A bacterial infection of the skin and subcutaneous tissues, cellulitis can cause swelling, redness, and warmth in the affected area. While a CT scan might not show the infection itself, clinical signs and symptoms are crucial for diagnosis.
• Rare Diagnoses
  • Sarcoidosis: A condition that can cause inflammation in various parts of the body, including the face, leading to swelling. It's less common and might require further testing for diagnosis.
  • Granulomatosis with Polyangiitis (formerly known as Wegener's Granulomatosis): A rare autoimmune disorder that can cause inflammation of the blood vessels and lead to swelling in the face among other symptoms. It's a rare condition that would require specific diagnostic tests.
  • Erythema Multiforme: A skin condition characterized by target-like lesions and can sometimes cause swelling, especially if it involves the face. It's relatively rare and has a distinct appearance that might not be captured by a CT scan.