Make new friends, but keep the old: Methotrexate treatment in psoriasis patients

Psoriasis is a chronic and inflammatory skin disease, with a current prevalence of 1.92% - 3.46% (Western Europe). There are different treatment options for psoriasis: topical therapy, phototherapy, systemic treatment with pills and biological treatment with subcutaneous injections.
The aim of this thesis was to study the systemic treatment option methotrexate in psoriasis vulgaris and other dermatological diseases. Due to the low treatment costs of methotrexate, this drug has the ability to keep dermatological healthcare affordable and accessible. Methotrexate was investigated by summarizing the evidence for the off-label use of methotrexate and the dosing of this drug used in psoriasis patients. In this thesis, we also tried to reach international consensus on the dosing regimen of methotrexate, and we investigated the long-term effects of the combination of methotrexate with adalimumab (adalimumab is a better affordable biological since biosimilars are available). In the last part, shared decision making for the systemic treatment decisions in psoriasis was studied.