[Diagnosis of infectious lymphadenitis]

Adenitis is a common disorder requesting numerous medical specialties. Etiologies are dominated by viral and bacterial infections, and more rarely parasitic, or by neoplastic and inflammatory diseases. Nevertheless, etiology remains often unknown and invasive tests may be required. On nodal tissue sample, histological examination, culture and polymerase chain reaction (PCR) are realized. PCR has revolutionized the diagnostic approach and consequently, knowledge of infectious lymphadenopathy. Previously, staphylococcus, streptococcus and mycobacterium were the main infectious agents identified in lymph nodes. Since its use, new emergent microorganisms responsible of lymphadenitis have been identified. Bartonella henselae, responsible of cat scratch disease, is to date the infectious agent most often encountered in adenitis. Mycobacterium avium subsp. hominisuis has been recently described as responsible of children lymphadenitis. PCR has become an essential tool in the diagnostic process of infectious lymphadenitis. Here, we propose a literature review on infectious adenitis and we emphasize the diagnostic strategy of adenitis.