Study design comprising an open phase and a controlled-randomized, double-blinded withdrawal. (A) Five patients were included in the pilot study, all of them harboring a mutation in K14 protein position 125. Initial blister numbers are given. *Note that, contradictory to an aforegoing patient inquiry, patient DIDM005 did not have any blisters at the first measurement. (B) Representative pictures of the right armpit of DIDM002 during t1 and t8. (C) The pilot study was a two-phase study with a 6 weeks open phase (P1), followed by a six-weeks double-blinded, randomized and controlled phase (P2). During P1, patients daily applied 1% diacerein cream underneath both armpits. During P2, one armpit of each patient was assigned to placebo in a double-blinded and randomized manner. For further data analysis, the study was divided into eight equidistant time spans (t), each comprising six counts. Patients counted blisters every second day, starting from day 1.