We’ve previously discussed several issues around psoriasis, including the pathogenesis of the condition and the challenges (and solutions!) of conducting psoriasis clinical trials. Today we turn toward three strategies for treating it. Although moisturizer may be an effective solution for some cases of mild psoriasis, many patients require medical intervention to ease their symptoms and address the inflammatory process underlying the condition.
Topical Treatments
Topical treatments may be used alone or in combination with other therapies. Topical corticosteroids and vitamin D derivatives are the standard treatment for mild to moderate psoriasis. Other less commonly used topicals include anthralin, coal tar, emollients, salicylic acid, and tazarotene.
Topical corticosteroids have been used to treat psoriasis since 1951 and have become the standard treatment for inflammatory skin diseases in general. They are available in a variety of strengths and formulations. While the most frequently prescribed medications for mild to moderate psoriasis, topical corticosteroids do not tend to be effective for treating moderate to severe psoriasis. These drugs slow down cell turnover by suppressing the immune system, reducing inflammation, and relieving itchiness.
Synthetic forms of vitamin D, such as calcipotriene and calcitriol, are another common psoriasis treatment. They work as cell differentiators, helping to slow down and correct hyperproliferation in skin cells. These drugs can be used long term but also frequently cause irritation.
Oral Medications
A chemotherapy drug that works as an immune system suppressant, methotrexate for psoriasis treatment became common in the 1970s. Despite a half-century of use, there is very little clinical data characterizing its safety and efficacy in psoriasis. However, recent meta-analyses have found that over 45 percent of patients achieve a 75 percent reduction in psoriasis severity and area scores after 12 to 16 weeks. Unfortunately, severe adverse events limit treatment with methotrexate in approximately seven percent of patients treated for six months. Rare but serious side effects seen in methotrexate treatment include irreversible liver damage and immune system suppression.
Cyclosporine was originally used to prevent rejection in organ transplant recipients and in 1997 became approved for use in patients with severe psoriasis and otherwise healthy immune systems. Patients taking this drug see a quick onset of results, but the condition almost always returns after treatment is discontinued. Additionally, patients on cyclosporine have an increased risk of developing skin cancer or lymphoma if they have previously undergone treatment with phototherapy, methotrexate, other immunosuppressive agents, or radiation therapy. Consequently, cyclosporine should only be used as a short-term therapy in the absence of other treatment options.
Phototherapy
Moderate to severe psoriasis often indicates the use of phototherapy, which uses ultraviolet light to slow the growth of new skin cells. This strategy includes narrow-band and broad-band shortwave ultraviolet B (UVB) and longwave ultraviolet A (UVA). UVB may be used alone or in combination with topical treatments, such as tar and anthralin. In contrast, UVA penetrates the skin more deeply and is typically used in conjunction with psoralen drugs
Be sure to read our white paper on the changing landscape of psoriasis treatment for more information on this condition, as well as major strategies for combating it.