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?

**Core Concept:** Angioedema is a clinical condition characterized by localized, transient swelling of the skin, mucous membranes, and subcutaneous tissues due to excessive leakage of plasma proteins into the extracellular space. It can be caused by various factors, including medications. Cephalexin is a penicillin antibiotic that can cause angioedema as a rare but serious adverse reaction.

**Why the Correct Answer is Right:** The patient presented with a history of finger pain and redness after taking cephalexin, followed by difficulty breathing and angioedema. His symptoms match the clinical picture of an angioedema event due to a drug reaction to cephalexin. Angioedema typically presents with swelling in the affected area, which in this case is the finger, and generalized symptoms like difficulty breathing.

**Why Each Wrong Option is Incorrect:**

A. Angioedema is usually non-pitting edema, which means it does not leave an indentation when pressed with a finger. In this case, the patient's angioedema involves the finger, which is not consistent with this characteristic feature of angioedema.

B. Swelling alone is not specific to angioedema and can be seen in other conditions like cellulitis, which is a bacterial infection. In this case, the patient has angioedema due to cephalexin usage, making cellulitis less likely.

C. Angioedema is often associated with urticaria (hives) due to the release of histamine and other mediators from activated mast cells and basophils. In this case, the patient does not have urticarial lesions, further supporting the diagnosis of angioedema due to cephalexin.

D. Angioedema can be life-threatening, particularly when involving the airway or face. In this case, the patient presents with difficulty breathing, which is a severe manifestation of angioedema and supports the diagnosis.

**Clinical Pearl:** Drug-induced angioedema can be a severe and potentially life-threatening reaction, especially when affecting the airway or face. It is essential to recognize these reactions promptly to initiate appropriate treatment and prevent complications. In this case, the patient's presentation with difficulty breathing suggests a severe reaction, prompting further evaluation and management.

**Correct Answer:** D. Difficulty breathing is a life-threatening manifestation of angioedema, particularly when affecting the airway or face. In this case, the patient presents with difficulty breathing, which supports the diagnosis of an angioedema reaction to cephalexin.

✓ Correct Answer: D. involvement of lips, tongue, eyelids, genitalia, and dorsum of hands or feet