In Reply We are pleased to see that our article1 has evoked a relevant discussion on the naming of bullous pemphigoid (BP) and its nonbullous variants.
Borrardori and Joly question in their letter whether patients can be definitively diagnosed as having BP solely on the basis of positive immunoserologic findings, since other chronic itchy dermatoses also produce positive results. An important nuance should be noted in this regard. In our study, all 4 patients had positive epidermal binding by indirect immunofluorescence (IF) on salt-split skin (SSS), whereas in the referred study,5 there was only a single positive finding in an enzyme-linked immunosorbent assay (ELISA) with NC16A and/or BP230 as substrate. False positive findings of BP180 and BP230 may occur because of nonspecific IgG binding, whereas indirect IF analysis using salt-split healthy skin has a 100% positive-predictive value.2 Moreover, direct IF of a skin biopsy specimen may result in a false negative finding as a result of sample error, as was found in 1 of the patients whose direct IF result was positive in the biopsy of a papule but not in that of healthy skin.1
Bakker CV, Terra JB, Jonkman MF. Toward a Practical Renaming of Bullous Pemphigoid and All Its Variants—Reply. JAMA Dermatol. 2014;150(4):459-460. doi:10.1001/jamadermatol.2014.54