Background: Cutaneous manifestations occurring in infections due to Yersinia enterocolitica are usually erythema nodosum, erythema multiforme or cutaneous vasculitis. The association between Yersinia infection and Sweet's syndrome is rare. We describe such a case contributing to the discussion on this association.

Methods: A 29-year-old woman had a papulo-pustular eruption with fever associated with arthralgia. The results of the infectious laboratory investigations were negative but Yersinia enterocolitica type 0.9 was isolated from a stool culture. The serologic diagnosis of Yersinia enterocolitica using serum agglutinins was negative. The diagnosis of Sweet's syndrome was made on a skin biopsy specimen. Search for hematology disease or underlying neoplasia was negative. The clinical course was rapidly favorable with antibiotic treatment (ciprofloxacin).

Conclusions: The diagnosis of Yersinia enterocolitica infection is difficult. Microbiologic diagnosis of Yersinia infection is best achieved by isolation of the bacterium from a clinical specimen of involved tissue. The agglutination test is not highly specific or sensitive. Immunoblotting appears to be more sensitive.