Propylthiouracil-induced ANCA-negative cutaneous small vessel vasculitis.

Area of Science:

• Endocrinology
• Rheumatology
• Dermatology

Background:

• Propylthiouracil (PTU) is a key treatment for hyperthyroidism.
• PTU can trigger autoimmune reactions, including drug-induced lupus and vasculitis.
• PTU-induced vasculitis presents a diagnostic challenge with significant morbidity risks.

Observation:

• Vasculitis induced by PTU typically manifests as cutaneous leukocytoclastic vasculitis.
• While often skin-limited, PTU-induced vasculitis can involve kidneys and lungs.
• This report details a rare instance of antineutrophil cytoplasm antibody-negative vasculitis linked to PTU.

Findings:

• Discontinuation of PTU is the primary treatment, often leading to symptom resolution.
• Most cases resolve within weeks, but some may become chronic or recurrent.
• Aggressive immunosuppressive therapy is reserved for refractory cases or those with organ involvement.

Implications:

• Early recognition and cessation of PTU are crucial for managing autoimmune side effects.
• Prompt diagnosis is essential for appropriate patient management and preventing severe outcomes.
• This case underscores the importance of considering PTU as a potential cause of vasculitis, even in antibody-negative presentations.