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Published on: December 15, 2011
Acute mucocutaneous methotrexate toxicity associated with interface dermatitis and numerous eosinophils
Nkanyezi N Ferguson1, Adam Asarch, Marta VanBeek
1Department of Dermatology, University of Iowa Hospital and Clinics, Iowa City, IA 52242, USA. nkanyezi-ferguson@uiowa.edu
Acute mucocutaneous methotrexate toxicity can present with interface dermatitis and eosinophils, challenging typical presentations. This case highlights the importance of considering these findings in patients on methotrexate therapy.
Area of Science:
- Dermatology
- Toxicology
- Pathology
Background:
- Methotrexate is a common treatment for psoriasis vulgaris.
- Acute mucocutaneous methotrexate toxicity typically presents with erosions and interface dermatitis.
- Prominent tissue eosinophilia is not a classic feature of this toxicity.
Observation:
- A 79-year-old male on methotrexate developed blisters and erosions on oral mucosa, groin, and extremities.
- Laboratory tests revealed pancytopenia, megaloblastic anemia, and elevated liver function tests.
- Skin biopsy showed psoriasiform hyperplasia, interface dermatitis, dyskeratotic keratinocytes, and numerous eosinophils.
Findings:
- The case demonstrates acute methotrexate toxicity with pancytopenia and mucocutaneous erosion.
- Histopathology revealed interface dermatitis and a significant eosinophilic infiltrate.
- Direct immunofluorescence was negative for immunoreactant deposition.
Implications:
- This case expands the histopathologic spectrum of acute mucocutaneous methotrexate toxicity.
- It suggests considering methotrexate toxicity in the differential diagnosis of interface dermatitis with eosinophilia.
- Prompt recognition and treatment with leucovorin can lead to clinical improvement.
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