Patients with rosacea have an increase in both cathelicidin and kallikrein 5 (KLK5, the serine protease that can cleave cathelicidin precursor protein into the active form), leading to the generation of the pro‐inflammatory forms of antimicrobial peptide (e.g., LL37) (Yamasaki et al,2007; Morizane et al,2010). Here, KLK5 is linked to rosacea.