A 27-year-old woman presents with a subtle discoloration of the lips.
The lesions began following sun exposure and have been present for 1 month. There is no history of similar lesions. However, the patient reports that she has had recurrent intraoral lesions and intermittent “enlargement” of the right side of her neck. She also reports a periodic lip lesion (plaque) with normal coloration that is associated with itching and episodic fever blisters; these occur with cold symptoms and lip urticaria. She self-prescribes tincture of benzoin and takes prescribed acyclovir (Zovirax) and an antibiotic when these symptoms flare.
Her medical history is unremarkable. She takes oral contraceptives.
Examination reveals a slightly elevated 0.5- to 1-cm lesion with subtle whitened striae that extend to the vermillion border of the maxillary lip and 2 areas localized to the mandibular lip. No other dermal or oral lesions are present.
What disorders would you consider in the differential, and how would you confirm the diagnosis?