Continuous versus intermittent therapy for moderate-to-severe psoriasis

Psoriasis is a chronic immune-mediated inflammatory disease of unknown etiology. Unlike other chronic inflammatory diseases receiving continuous treatment, psoriasis has traditionally been treated intermittently secondary to concern for cumulative toxicity of conventional systemic therapies. However, the development of targeted antiinflammatory biologic agents allowed for continuous therapy for most patients. Herein, we review the literature for intermittent versus continuous use of widely available therapies for moderate- to-severe psoriasis: phototherapy, topical corticosteroids, conventional systemic therapies and biologic agents. These data support continuous treatment in biologic therapy, such as etanercept, adalimumab, infliximab, and ustekinumab. Intermittent therapy with biologic agents leads to decreased efficacy and sometimes increased side effects. When conventional systemic therapy is used continuously, it is more efficacious; however the data support intermittent use of methotrexate and cyclosporine due to cumulative toxicities. Psoriasis severity may wax and wane, but it is a chronic disease requiring continuous treatment for optimal control of inflammatory activity and to minimise cutaneous involvement.