Biologics and Small Molecule Agents in Allergic and Immunologic Skin Diseases

Biologics and small molecules are key therapeutic options in the treatment of chronic immunologic and allergic skin conditions. By directly targeting innate and inflammatory responses within the skin, including pro-inflammatory cytokines and cellular signaling pathways, these new agents have the potential to counteract the inflammatory cascade responsible for various conditions, including psoriasis and atopic dermatitis. Over the past decade, groundbreaking research identifying key cytokines and receptors involved in the pathogenesis of these diseases has allowed for the development of highly efficacious biologics and small molecules that are associated with unprecedented rates of skin clearance and favorable adverse event profiles.

This narrative review evaluates new and upcoming biologic and small molecule agents for the treatment of two allergic/immunologic skin diseases-atopic dermatitis and psoriasis. Numerous small molecules and biologics targeting TNF-α, IL-12/23, IL-17 and IL-17R, and IL-23 are commercially available for the treatment of psoriasis, and newer agents are in various stages of development. Currently, dupilumab, a monoclonal antibody that blocks IL-4R∝, is the only approved biologic for atopic dermatitis. Antibodies targeting IL-13 and IL-31 and small molecules that inhibit Janus kinase and pruritus-mediating receptors are currently being studied in clinical trials. Further investigations into the pathophysiology of atopic dermatitis will likely yield additional therapeutic options in the future. This article reviews recent literature on small molecules and biologics for the treatment of atopic dermatitis and psoriasis.