Blistering rash in an older man
The patient kept hoping that the rash would go away on its own, but as time went by the rash spread and the pain became intolerable.
Biopsy confirms the Dx
A biopsy of a lesion confirms the diagnosis of BP and will help differentiate it from the conditions mentioned above.
Light microscopy shows eosinophil-rich subepidermal inflammatory infiltrate.2 Direct immunofluorescence displays the characteristic linear deposits of IgG and complement C3 along the basement membrane. Immunofluorescent testing on human salt-split skin may also be performed.
Drug induced? There is a subset of BP, called drug-induced BP, in which the onset of the disease is associated with the initiation of a medication. Furosemide is the most common culprit,3 although many additional medications have been described.
The pathophysiology of drug-induced BP is poorly understood.3 In some cases, discontinuation of the offending medication may halt progression and prevent recurrence. In other cases, the disease will progress to a chronic form regardless of medication discontinuation. It is reasonable to attempt medication discontinuation trials in cases where drug-induced BP is suspected.
