Cytokine blocking therapies have revolutionized the management of psoriasis and atopic dermatitis but can lead to the development of paradoxic psoriasis (PP). Patients treated with biologics should be closely monitored for the development of PP and other paradoxical eruptions (including inflammatory joint disease, inflammatory bowel disease, eczematous eruptions, lupus like eruptions, sarcoidal eruptions, and others) and occasionally the development of cutaneous T-cell lymphoma. Further understanding the immunologic mechanism of these processes will ultimately drive our understanding of and ability to predict and manage PPs.