Acute Exacerbation of Erythrodermic Psoriasis with Phototherapy: Pathophysiology and Results of a National Psoriasis Foundation Survey regarding Photo-Management of Erythrodermic Skin

Abstract

The phenomenon whereby phototherapy exacerbates instead of reduces intensely inflamed skin may be known to most, but not all, phototherapy providers. Furthermore, it has never been articulated or named in the literature. We report a patient with near-erythrodermic psoriatic skin which became fully erythrodermic after one treatment with narrowband UVB, and the results of a survey study disseminated to all phototherapy practitioners registered with the National Psoriasis Foundation. We propose the name “hyper-photosensitivity threshold” to refer to the aforementioned phenomenon. Fifty-six percent of our survey respondents reported having observed this phenomenon and the following “cooling” procedures to reduce the intense inflammation of erythrodermic skin: topical corticosteroids, cyclosporine, wet wraps, and systemic medications other than cyclosporine, ranging from systemic steroids and methotrexate to mycophenolate mofetil. We hope that this knowledge will help future generations of phototherapy practitioners treat intensely inflamed skin properly and avoid unwanted adverse effects.