In Reply We appreciate the comments from Waseh et al on our modified Delphi consensus article regarding the definition and diagnostic criteria for generalized pustular psoriasis (GPP).1 All concerns raised have been thoroughly discussed by GPP experts from 5 continents, and the article transparently presents the level of consensus reached.
We maintain, with 96% agreement, that Sneddon-Wilkinson disease (SWD) should remain distinct from GPP due to its unique characteristics, such as flaccid pustules with hypopyon formation and the absence of spongiosis, unlike the spongiform microabscesses seen in GPP. Additionally, the association of GPP with psoriasis vulgaris, confirmed by multiple studies, has not been reported for SWD, which is linked to monoclonal gammopathies and other immune-mediated conditions.2,3 We disagree that SWD is merely a historic entity; its unique characteristics, including hypopyon pustules and flexural predominance as well as the absence of acantholysis and negative direct and indirect immunofluorescence clearly distinguish it from IgA pemphigus.