"Cowboy's belt with revolver" scleroderma caused by vitamin K1 injections.

Vitamin K1 (phytomenadione or phytonadione) is a fat soluble vitamin used to treat certain coagulation disorders. Intra muscular injection of vitamin K1 can occasionally be complicated by different types of skin reactions: erythematous plaques, urticarial rashes or scleroderma-like lesions at the injection site. We report the case of a 52-year-old man presenting with 2 symmetrical erythematous-infiltrated scleroderma-like plaques localized on the right and left lower trunk. To correct the coagulation deficiency with hypoprothrombinemia developed as a consequence of HCV+ hepatitis, the patient was on vitamin K1 therapy, administered by i.m. injection (10 mg Vitamin K1/1 ml) once a day for 2 weeks. Three months after treatment interruption, ivory indurated morphoeiform plaques developed at the injection sites, assuming the typical appearance of a "cowboy's belt with revolver". The scleroderma-like lesions persisted 2 years after vitamin K1 withdrawal. We report this case to highlight the possibility that vitamin K1 injections can occasionally be complicated by different types of skin reactions such as sclerodermatous plaques. Due to the delay in the onset, to the variable clinical picture, to the persistence after therapy interruption, this kind of lesions can represent a tricky diagnostic challenge and in spite of different treatments can endure for years.