Psoriasiform adult blaschkitis triggered by adalimumab: a rare paradoxical reaction

Psoriasiform adult blaschkitis triggered by adalimumab: a rare paradoxical reaction ଝ Dear Editor,Blaschkitis is an acquired, self-limited inflammatory dermatosis that follows Blaschko's lines, typically affecting adults and involving the trunk.Although its pathogenesis remains unclear, it has been associated with biologic therapies.These paradoxical cutaneous reactions have been reported with Tumor Necrosis Factor Alpha (TNF␣) inhibitors such as infliximab, etanercept, certolizumab and adalimumab.1,2 A 74-year-old woman with seronegative spondyloarthritis, on adalimumab for three months, developed a gradually progressive, pruritic, erythematous desquamative eruption following Blaschko's lines on the right trunk (Fig. 1A), with sharp midline demarcation (Fig. 1B).It appeared three months after initiating adalimumab and resolved completely, and without sequelae, following drug discon-