Occurrence of PsoriasiformEruption DuringNivolumab Therapy for Primary OralMucosalMelanoma

described in the Japanese population, several PP cases have also been reported in Western countries and, recently, in the Middle East.2,3 Thepathogenesis of PP is not completely clear. In addition to being associated with several factors including exogenous (physical trauma, friction)andhormonal (pregnancy,menstruation),PPhasclassicallybeenreported inassociationwithmetabolic derangements, especially ketotic states (dieting, fasting, diabetesmellitus).2,3Actually, several studieshavedetectedelevated urine and/or blood ketone levels in patients with PP.2,3 Insuchcircumstances, it isbelievedthatketonebodiesmaydistributearoundbloodvessels leading toperivascular inflammation or enter into cells modifying their intracytoplasmic processes. The inflammation is believed tobemainlymediatedby neutrophils: PP usually respondswell tomedicationswith antineutrophil effect, such as dapsone and tetracyclines, which would support this neutrophil-mediated theory. A role for decreased insulin levels, which is reported to occur after bariatric surgery,4 has also been hypothesized as cause of PP.2 Inaddition to its effect in changing thecourseofmanyskin diseases such as psoriasis, bariatric surgery has been associatedwith several dermatoses includingbowel-associateddermatosis–arthritis syndrome, nutritional deficiency dermatoses, and alopecia.5However, PPhas never been reported after bariatric surgery. Given that such surgery may easily replicate the metabolic disturbance associated with other ketotic states such as dieting or fasting,5,6 we believe that the association between PP and bariatric surgery may be underdiagnosed or underreported. In conclusion, to our knowledge, this report is the first to describePPdevelopingafter bariatric surgery, addingPP to the cutaneouscomplicationsof suchprocedures. Increasedawareness of this rare entity and this association is important becausebariatric surgery is a commonprocedurenowadays, and themetabolic abnormalities accompanying itmimic those that occur with other ketotic states.