As an addition to discussion regarding skin changes on brinsupri:
Research found in the autosomal recessive immunodeficiency Papillon–Lefevre syndrome (PLS), the affected children almost invariably present with intractable suppurative gum infections (chronic gingivitis) that lead to loss of teeth by the age of 6–8 years (Pham et al., 2004; Pham, 2006). DPP1 is also expressed at high levels in the skin, and marked thickening of the skin of the palms and soles (hyperkeratosis) can result from failed keratinocyte desquamation at these sites.
a mutation in the DPP1 gene (CTSC), results in diffuse palmoplantar hyperkeratosis, severe prepubertal periodontitis, and premature loss of both deciduous and permanent teeth
Drugs like brinsupri depresses DPP 1 causing the skin and gum problems in people with PL.