Nitrosamine (and/or Irbesartan) Induced Large Plaque Parapsoriasis and Urothelial Carcinoma: First Report in the Medical Literature!

A presenting case of a 64-year-old gentleman with a complaint of disseminated skin rash on the trunk, upper and lower limbs. He was diagnosed with type II hypertension in January 2017 and was started on irbesartan 150 mg one oral tablet daily (1-0-0). After 6 months, this dose was reduced to half a tablet which he continues to take to this day. He was also diagnosed with type two diabetes mellitus for which he is actively treated with metformin 1500 mg (1-1-1) daily. The patient noticed subtle skin changes in 2019 and upon seeking medical advice, he was diagnosed with an incidental finding of low grade papillary urothelial carcinoma, (T1 N0 M0). He was subsequently treated with transurethral surgical interventions and hospitalised for four different sessions before being sent to our dermatological clinic for evaluation of the skin condition. On examination, multiple large psoriasiform plaques were observed bilaterally, predominantly on the trunk, upper and lower extremities (Figure A-D), the greatest measuring approximately 6 cm in diameter. The plaques were variable in size and polymorphic in nature exhibiting a salmon-pink discoloration. There were no signs of pruritis or poikilodermatous changes. Based on the clinical data, a drug-induced parapsoriasis was suspected. Histopathological examination revealed generalised parakeratosis with perivascular lymphocytic infiltrations in the upper dermis. No signs of mycosis fungoides was noted, keeping in line with a clinicopathological diagnosis of large plaque parapsoriasis.