Methotrexate-Induced Cutaneous Toxicity

Clinical Presentation and Management

• The American College of Dermatology recommends checking CBC with differential urgently, as methotrexate-induced pancytopenia can occur after even a single dose and typically manifests early in treatment (first 4-6 weeks) 1
• The National Kidney Foundation suggests monitoring renal function closely, as decreased function increases methotrexate levels and toxicity 2
• The American Academy of Dermatology recommends considering leucovorin (folinic acid) rescue if severe toxicity is suspected, and filgrastim for toxic bone marrow suppression 1
• The Infectious Diseases Society of America notes that methotrexate increases infection risk, and patients should be monitored for signs of infection given immunosuppression risk 3, 2
• The American College of Dermatology advises that alternative immunosuppressive agents should be considered for the underlying condition requiring treatment, as patients who experience severe reactions should never receive methotrexate again 4, 5