A 44-year-old woman presented to the emergency department with a two-day history of lower lip swelling. She had pain and warmth in her lip but no fever, chills, or other symptoms. She had recently completed a course of trimethoprim/sulfamethoxazole for a urinary tract infection. Although she had a history of similar lower lip swelling after angiotensin-converting enzyme inhibitor use, she said she had not taken them recently. She had no history of fillers or other cosmetic treatments to the lip or face.

She was afebrile on physical examination. Her lower lip was edematous, and tense and tender to palpation. The exposed mucosa was dry and cracked, with scabbed-over skin just caudal to the vermilion border (Figure 1). Enlarged, mildly tender lymph nodes were palpable in her neck.

Question

Based on the patient's history and physical examination findings, which one of the following is the most likely diagnosis?

• A. Angioedema.

• B. Cutaneous sarcoidosis.

• C. Lip abscess.

• D. Type I hypersensitivity reaction.