TNF‐α concentrations of the three sera were determined by ELISA as healthy control 2.92 pg/mL (0.29 pg/mL final concentration), lichenoid dermatitis 9.17 pg/mL (0.92 pg/mL final concentration), and SJS/TEN 12.25 pg/mL (1.22 pg/mL final concentration). This evidence concerns the gene TNF and toxic epidermal necrolysis.