Successful Treatment of Erythroderma in a Psoriasis Patient, Developed After Anti‐IL‐17, Anti‐IL‐23 and Anti‐IL‐4/IL‐13 Treatment, With Deucravacitinib

ABSTRACT We present the case of a 79‐year‐old female patient diagnosed with psoriasis who developed paradoxical drug reactions after administration of anti‐IL17 and anti‐IL‐23 inhibitors. Having shifted towards a rather eczematous phenotype, the patient received an anti‐IL‐4/IL‐3 inhibitor, subsequently developing erythroderma. This patient had a history of lichen planus 20 years prior, which was not present clinically during the following years. The skin lesions in this patient resolved significantly after initiation of the TYK2 inhibitor deucravacitinib, possibly because this drug inhibits inflammatory factors typical of psoriasis (IL‐17, IL‐23) as well as key cytokines of lichen planus (CXCL10).