Mercaptopurine-induced Sweet's syndrome.

Area of Science:

• Dermatology
• Gastroenterology
• Pharmacology

Background:

• Sweet's syndrome is an acute febrile neutrophilic dermatosis.
• Drug-induced Sweet's syndrome is a known adverse reaction to various medications.
• Crohn's disease management often involves immunosuppressive agents.

Observation:

• A man in his early 40s with newly diagnosed Crohn's disease developed fever and a widespread rash.
• The patient had recently started 6-mercaptopurine treatment.
• Skin biopsy revealed characteristic neutrophilic infiltration, edema, and fibrin deposition.

Findings:

• The patient's symptoms rapidly resolved upon discontinuation of 6-mercaptopurine.
• Systemic corticosteroids were not required for treatment.
• This suggests a direct causal link between 6-mercaptopurine and the observed Sweet's syndrome.

Implications:

• Highlights the importance of considering drug-induced Sweet's syndrome in patients with Crohn's disease on immunosuppressants.
• Demonstrates the efficacy of drug withdrawal as a primary treatment strategy.
• Informs clinical practice regarding differential diagnosis and management of dermatological adverse events in inflammatory bowel disease patients.