Hypereosinophilia as a Rare Side Effect of Methotrexate in a Patient with Erythrodermic Psoriasis: The First Case Report

Methotrexate (MTX) has been approved for the treatment of psoriasis and is considered to be effective and relatively safe. This drug was widely used for treatment of psoriasis in Vietnam for many years. Life-threatening MTX toxicity is rare but may rapidly develop when the drug is administered. In line with the interface dermatitis and a remarked eosinophilic infiltration in the cutaneous lesion, the diagnosis of hypereosinophilia as an adverse reaction in our patient was supported by the dramatic improvement of symptoms and decreased eosinophils after withdrawal of MTX. To the best of our knowledge, this is the first case that showed isolated hypereosinophilia as an adverse reaction of MTX in psoriasis treatment that may challenge in early recognition. Awareness and prompt recognition of this severe adverse reaction can result in life-saving discontinuation of MTX.