To provide an update on the possible role of nanoparticles as sensitizing occupational agents and on the influence of nanoparticles-exposure on the appearance/exacerbation of occupational allergy. Recent case reports, epidemiological studies, and experimental investigations in cellular and animal models demonstrated the potential for nanomaterials to favor/interfere with occupational allergy. First data are emerging on the sensitizing potential of nanoparticles that can act as haptens linking to proteins, with a formation of a 'corona'. Nanoparticles with carrier protein become a complete antigen and induce specific immune response. Moreover, they act as adjuvant favoring sensitization to bound molecules. The disruption of the respiratory and skin barrier, the modulation of immune response toward Th1 or Th2 immune reaction and the interaction with immune effector cells (mast cells and eosinophil in particular) can explain the potential for nanoparticles to exacerbate pre-existing allergic conditions. the exposure to nanoparticles represents a possible risk for occupational allergy both in the respiratory tract and in the skin. A deeper knowledge on the role of nanomaterials in the etiology/development of the allergic disease will allow to implement risk assessment and preventive measures for nanosafety in the contest of technological expansion.