A patient presents with grouped vesicles on an erythematous base, affecting the lips and perioral region. The patient reports a history of similar episodes triggered by sunlight exposure and stress. Which of the following conditions is most likely responsible for this presentation?
Correct Answer: A
Rationale: The patient's presentation with grouped vesicles on an erythematous base affecting the lips and perioral region, triggered by sunlight exposure and stress, is classic for herpes simplex labialis, commonly known as cold sores. Herpes simplex virus type 1 (HSV-1) is responsible for cold sores and is highly contagious. Recurrent episodes can be triggered by factors like UV exposure, stress, illness, and hormonal changes. Symptoms typically start with tingling or burning sensations before progressing to grouped vesicles that rupture, forming crusts. Treatment may involve antiviral medications to reduce the severity and duration of symptoms. Perioral dermatitis typically presents with papules and pustules around the mouth, while angular cheilitis involves fissures and inflammation at the corners of the mouth. Allergic contact dermatitis would present with erythema, pruritus, and possibly vesicles in