Which medication is the primary systemic therapy for severe psoriasis?

Methotrexate is considered the primary systemic therapy for severe psoriasis due to its long-standing use and effectiveness in managing the condition. It works by inhibiting DNA synthesis and cell proliferation, particularly affecting rapidly dividing cells like those found in psoriatic lesions. Methotrexate also demonstrates anti-inflammatory properties, which help reduce the immune system’s hyperactivity that characterizes psoriasis.

In patients with severe psoriasis, the need for systemic therapy arises when topical treatments are insufficient. Methotrexate is often chosen for its ability to provide significant improvement in psoriasis symptoms and because it can be used in various formulations, including oral and injectable forms. Additionally, it has established dosage guidelines and monitoring protocols, making it a practical choice for long-term management.

While other treatments like adalimumab, a biologic agent that targets specific components of the immune response, also have a place in treatment, methotrexate remains a cornerstone therapy due to its availability, cost-effectiveness, and robust track record in treating severe cases of psoriasis. Acitretin is an alternative treatment option but is generally not the first-line systemic therapy. Topical corticosteroids, while effective for localized cases of psoriasis, do not suffice as systemic therapies for severe manifestations.