AKT-1401

AKT-1401

A 35-year-old woman has developed a polymorphic eruption over the dorsa of both hands and feet. The lesions started 2 days ago and she now has some lesions on the arms and legs. Individual lesions are well-demarcated red macules or small urticarial plaques. Some lesions have a small blister or crusting in the centre, which seems darker than the periphery.
Select from the list the single most likely diagnosis.