Sweet's syndrome (SS) is an acute neutrophilic dermatosis characterised by abrupt onset of fever, leukocytosis and cutaneous eruption, with dermal neutrophilia on skin biopsy. Most cases are idiopathic but SS can be associated with various affections, especially neoplastic, inflammatory and infectious diseases. The authors report the case of an SS occurring in a patient with a known rheumatoid arthritis associated with a secondary Sjögren's syndrome, with incidental finding of concurrent lymph node tuberculosis. In case of SS, an associated disease (malignant, inflammatory or infectious diseases) must imperatively be searched for, knowing that two or more of these affections can coexist.