IFIH1 and dermatomyositis: Tacrolimus trough concentration‐escalating bipartite therapy (glucocorticoids combined with tacrolimus) and individualized mapping of the optimal tacrolimus trough concentration for each patient is a therapeutic strategy to be considered in patients with refractory anti‐melanoma differentiation‐associated gene 5 (MDA5) antibody‐positive clinically amyopathic dermatomyositis with rapidly progressive interstitial pneumonia.