A 42-year-old man was seen in the clinic because of pain and redness in his finger. Last week he had injured the finger while working in his garage. On physical examination, there is erythema, swelling, and tenderness of the second digit in the right hand. Flexion and extension of the finger were normal. A clinical diagnose of cellulitis is made and he is prescribed cephalexin. A few days later he presents to the emergency room complaining of difficulty breathing. He has angioedema due to a drug reaction to the cephalexin. Which of the following physical findings is characteristic of this syndrome?