Differential Diagnosis for Viral Illness with Lower Lip Swelling

• Single Most Likely Diagnosis
  • Viral infection with allergic or irritant reaction: This is the most likely diagnosis given the context of a viral illness followed by localized swelling, which could be due to an allergic reaction or an irritant causing the lip swelling.
• Other Likely Diagnoses
  • Angular cheilitis: This condition, often associated with viral infections, can cause inflammation and swelling at the corners of the mouth, potentially extending to the lower lip.
  • Herpes simplex virus (HSV) infection: HSV can cause cold sores, which often appear as swollen, red, and painful blisters on the lips, including the lower lip.
  • Hand, Foot, and Mouth Disease (HFMD): Although more common in children, HFMD can cause oral lesions and could potentially lead to lip swelling in the context of a viral illness.
• Do Not Miss Diagnoses
  • Angioedema: A potentially life-threatening condition that can cause rapid swelling of the lips, face, and airways. It's crucial to identify and treat promptly to avoid airway obstruction.
  • Cellulitis or abscess: Bacterial infections that can cause swelling, redness, and pain. In the context of a viral illness, a secondary bacterial infection could occur, leading to these conditions.
• Rare Diagnoses
  • Melkersson-Rosenthal syndrome: A rare neurological disorder characterized by recurrent, often unilateral, facial paralysis or weakness, swelling of the face and lips, and the development of folds and furrows in the tongue (fissured tongue).
  • Sarcoidosis: A condition where inflammatory cells form lumps known as granulomas in various parts of the body, including the skin, which could potentially cause lip swelling, although this would be an uncommon presentation.