Allopurinol-induced Sweet's syndrome

Area of Science:

• Dermatology
• Rheumatology
• Internal Medicine

Background:

• Sweet's syndrome, or acute febrile neutrophilic dermatosis, is an uncommon but severe cutaneous condition.
• It has not been previously associated with allopurinol therapy.

Observation:

• An 87-year-old woman with hyperuricemia developed symptoms of Sweet's syndrome 8 days after initiating allopurinol therapy.
• Symptoms included fever, painful edema, erythematous plaques with pustules, conjunctivitis, splenomegaly, and joint pain.
• Initial blood tests revealed neutrophilic leukocytosis, inflammation, and abnormal liver function.

Findings:

• The patient's condition did not improve with broad-spectrum antibiotics (ceftriaxone, levofloxacin).
• Intravenous methylprednisolone therapy resulted in rapid clinical improvement, pain reduction, fever resolution, and normalization of blood values.
• The Naranjo scale suggested a probable association between allopurinol use and the development of Sweet's syndrome.

Implications:

• This case suggests a potential, previously unreported association between allopurinol and Sweet's syndrome.
• The similar presentation of Sweet's syndrome to infections can lead to diagnostic delays and inappropriate antibiotic use.
• Early recognition and consideration of drug-induced causes, such as allopurinol, are crucial for timely and effective glucocorticoid treatment.