Biologics and Small Molecule Inhibitors: Novel Therapeutic Strategies for Cutaneous Adverse Drug Reactions

Cutaneous adverse drug reactions (cADRs) are unintended and harmful skin responses to medications that impose significant clinical and economic burdens worldwide. The increasing use of novel agents, particularly immune checkpoint inhibitors, has further compounded this challenge. While most cADRs are mild and resolve upon drug discontinuation, approximately 2-6.7% progress to severe, potentially fatal conditions. The most common severe forms include acute generalized exanthematous pustulosis, Stevens-Johnson syndrome/toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome, and drug-associated bullous pemphigoid. Current therapeutic options for refractory cADRs remain limited, primarily relying on systemic corticosteroids, conventional immunosuppressants, and intravenous immunoglobulin. Growing insights into disease pathogenesis and the subsequent repurposing of novel targeted therapies offer promising solutions to the persistent challenges of cADRs. Emerging agents, such as biologics targeting tumor necrosis factor-α, interleukins (IL-4/IL-13, IL-5, IL-6, IL-17, IL-36), immunoglobulin E, and CD20, along with small molecule inhibitors of Janus kinases and phosphodiesterase 4, hold the potential to revolutionize management paradigms, though their long-term efficacy and safety profiles await robust clinical validation.