Patients present with swelling, burning, or soreness at the vermilion border of the lips followed by the appearance of clusters of small painful vesicles on an erythematous base (Fig. 54.1). The vesicles can rupture to produce red, irregular ulcerations with swollen borders and crusting, which eventually heal without leaving a scar. These lesions can also occur on the hard palate or gingiva. Episodes may recur after exposure to sunlight or emotional or physical stress. The initial episode is usually the worst, with generalized malaise, low-grade fever, tender cervical adenopathy, and occasional exudative pharyngitis lasting 2 to 3 weeks. Recurrences are milder and shorter, with a prodrome of itching or burning at the lesion site. The painful ulcers that eventually form last 7 to 10 days.