ABSTRACT
In patients with moderate to severe psoriasis, combination, rotational, and sequential therapies rely on the use of lower-dose therapeutic agents to minimize toxicity. In the case of combination therapy, additive or synergistic effects may result in enhanced efficacy; however, the dangers of additive toxicity or of immunosuppression must be considered. Formally introduced by Dr. John Koo, the concept of sequential therapy makes use of a “rabbit to turtle” approach where the therapeutic strategy involves a deliberate sequence starting with a more efficacious but riskier agent. The concept of rotational therapy was first introduced by Weinstein and White. At that time, ultraviolet B plus tar, psoralen plus ultraviolet A, methotrexate, and etretinate were the treatments available for severe psoriasis. Weinstein and White advocated using each form of therapy for one to two years and then switching to the next form.
