Methimazole-Induced Leukocytoclastic Vasculitis: A Case Report
Weeratian Tawanwongsri1, Pamela Chayavichitsilp1
1Division of Dermatology, Department of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
Abstract:
Major identifiable causes of leukocytoclastic vasculitis include certain infections and medications. Amongst antithyroid drugs, methimazole (MMI) is rarely implicated as a culprit drug. We report the first case, in Thailand, of MMI-induced leukocytoclastic vasculitis in a 41-year-old Thai female who had received MMI for relapsed Graves' disease. MMI was discontinued and cholestyramine at a dose of 4 g four times daily was given instead. Her rashes on both legs resolved dramatically at 1-week follow-up. However, thyroid function test revealed unimproved thyrotoxicosis. She subsequently underwent radioiodine ablation as a definitive treatment. There were neither recurrent skin lesions nor other systemic involvements during the 3-month follow-up period. Notably, the most crucial step in the management of drug-induced leukocytoclastic vasculitis is the discontinuation of the offending drug in order to avoid further progression of the disease. The administration of immunosuppressive agents may not be necessary in patients with mild severity and non-vital organ involvement.
Insights
Methimazole (MMI), a rare cause of leukocytoclastic vasculitis, was identified in a Thai patient. Discontinuing MMI led to rapid rash resolution, highlighting early drug cessation as key for managing this condition.
Area of Science:
- Endocrinology
- Dermatology
- Pharmacology
Background:
- Leukocytoclastic vasculitis (LCV) is typically linked to infections or medications.
- Antithyroid drugs, particularly methimazole (MMI), are infrequently associated with LCV.
Observation:
- A 41-year-old Thai female with Graves' disease developed LCV after MMI treatment.
- The patient presented with characteristic skin rashes on both legs.
Findings:
- Discontinuation of MMI and administration of cholestyramine resulted in rapid resolution of LCV symptoms within one week.
- Thyroid function remained abnormal, necessitating radioiodine ablation for definitive Graves' disease management.
- No recurrence of skin lesions or systemic involvement was observed during a 3-month follow-up.
Implications:
- Early identification and cessation of the offending drug are paramount in managing drug-induced LCV.
- Immunosuppressive agents may not be required for mild LCV cases without vital organ involvement.
- This case underscores the importance of considering MMI as a potential cause of LCV in clinical practice.
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