Abstract
Methotrexate is an anchor-drug for the treatment of inflammatory arthritides affecting peripheral joints, such as rheumatoid and psoriatic arthritis (PsA), but also for other immune-mediated diseases like psoriasis. Although it is generally a well-tolerated drug, adverse effects often occur. Reversible derangement of liver function test is the most common laboratory adverse event. However, in some cases, liver cirrhosis and/or fibrosis can occur. Besides, many of these diseases like PsA and psoriasis are closely linked with clinical conditions and risk factors that also contribute to liver damage/cirrhosis, such as increased body mass index, dyslipidaemia and diabetes mellitus (DM). It has been hypothesised that the aforementioned risk factors along with methotrexate usage can act synergistically, causing liver damage in these patients. Herein, we describe a PsA patient with DM who developed fatal liver cirrhosis after 10 years of treatment with MTX. We also review the literature about the liver toxicity of MTX in the context of PsA and psoriasis, describing concurring risk factors and histopathological findings. PubMed and Scopus were searched, without date limits. The keywords "methotrexate" AND "psoriatic arthritis" OR "psoriasis" AND "Liver damage" OR "liver fibrosis" OR "cirrhosis" were used. We found that although fibrosis/cirrhosis is present in about 10-25% of the patients, MTX can rarely cause liver damage itself. However, it can exert its effect when other factors, like increased alcohol consumption and obesity coexist. Prospective studies are needed, specifically examining the hepatotoxicity of MTX in individuals with immune-mediated diseases.