Background: Acute febrile neutrophilic dermatosis (Sweet's syndrome) is very uncommon in infancy. Systemic corticosteroid treatment is the standard therapy, usually leading to dramatic improvement within a few days.
Case report: A seven-month-old female infant was admitted for investigation of a rash developing over ten days with fever. Physical examination and skin biopsy led to a diagnosis of Sweet's syndrome. The relative inefficiency of systemic corticotherapy induced the parents to stop all treatment.
Conclusion: This case report allows us: 1) to consider the clinical and biological features of Sweet's syndrome in infancy; 2) to describe a corticosteroid resistant disease; and 3) to observe the course of a spontaneous evolution of Sweet's syndrome.