Methotrexate is an effective chemotherapeutic drug for adults and children with moderate-to-severe eczema. It's advised as a third-line therapy since it prevents DNA, RNA, and purine production by inhibiting dihydrofolate reductase. In people with severe AD, MTX has demonstrated comparable efficacy to azathioprine and low-dose cyclosporine. To reduce toxicities, initial doses of 7.5 to 25 mg per week are advised, along with daily folic acid [4,126]. Here, DHFR is linked to Alzheimer disease.