Transition of psoriasiform drug eruption to psoriasis de novo evidenced by histopathology.

Drug reaction can be one of the triggering factors either for exacerbation of pre-existing psoriasis or precipitation of psoriasis de novo. Herein, we report a case with psoriasiform drug eruption due to pravastatin, but it relapsed after discontinuance of the drug. Serial investigation of the histopathology and immunohistochemistry with anti-signal transducer and activator of transcription 3 (STAT3) revealed drug reaction-associated lesions intermingled with psoriasiform changes, which later predominated, suggesting a conversion into psoriasis de novo.