How Safe Is Taking Flecainide For Atrial Fibrillation?

my wife has been on flecainide for 5 years for atrial fibrillation and in february developed a rash mainly on her arms and legs and to a lesser extent on her chest. It is worse in the sun,. The dermatologists at a joint meeting in Sydney recently think that it is an allergy to the flecainide. is this reasonable. However a biopsy of the lesion showed mixed immunofluorescence in the dermoepidermal junction favouring lupus erythematosus.