Microneedles for psoriasis: from barrier bypass to programmable lesion pharmacology

Psoriasis is a chronic inflammatory dermatosis in which epidermal hyperplasia and barrier dysfunction reduce topical drug penetration and compromise treatment adherence. Systemic therapies, including biologics, can achieve disease control, but their use is constrained by parenteral administration, high cost, and off-target exposure. Microneedle (MN) arrays offer a minimally invasive strategy to bypass the stratum corneum and enable controlled intradermal delivery, thereby increasing local drug exposure and residence time while facilitating self-administration. This review summarizes psoriasis-relevant pathobiology, with an emphasis on immune cell–cytokine circuits and barrier impairment, and discusses how MN engineering can overcome delivery constraints and support local immunomodulation. We compare the major MN types—solid, hollow, coated, dissolving, and swellable systems—and describe representative MN-enabled delivery strategies for small molecules, biologics, and nucleic acids. These approaches are designed to enhance lesion retention, provide sustained release, and promote barrier repair. We also assess stimuli-responsive MN platforms, including reactive oxygen species- and pH-responsive systems, that couple drug release kinetics to the inflammatory microenvironment. Finally, we discuss key translational requirements, including scalable manufacturing, dose uniformity, sterilization, stability, human factors, and regulatory considerations for combination products. Current human evidence remains limited and is derived mainly from an indication-specific nail psoriasis study. Future research should prioritize standardized product characterization, long-term safety assessment, and well-designed clinical studies to establish therapeutic efficacy and patient acceptability. Collectively, MNs represent a promising platform for site-specific psoriasis therapy, although their clinical impact will depend on robust product development and clinical validation.