The nail unit is the most commonly affected area in hand infections, which can be primary infection or superinfection complicating other nail or skin disorders. Trauma, mechanical or chemical, is usually the trigger enabling infiltration of infectious organisms. Artificial nails and nail polish are also a possible cause of bacterial infection, harboring microorganisms. In severe acute bacterial infection, surgical intervention is often needed to prevent morbidity and disability. Abscess should always be drained, but viral infection such as herpetic whitlow, may mimic an abscess and, in contrast, requires non-operative treatment; to prevent sequelae. A more conservative approach is also generally advisable in less severe bacterial infection, other viral infections and in subacute or chronic nail infection. The present review deals with acute, subacute and chronic bacterial and viral infections of the nail unit, with a focus on diagnostic and treatment options.

III, systematic review of level III studies.