[The diagnosis of diseases due to occupation]

Occupational diseases are essentially defined by aetiological characteristics, and not by nosological characteristics, because the latter in most cases are not specific. This is particularly so for "work-related" diseases but still stays true for most "occupational" diseases. This implies that the diagnostic path for occupational diseases must include one additional step as compared to the standard procedure typical of non occupational medicine. The last is satisfactory after a suitable history and clinical-instrumental phase and thus a nosological definition are completed. The former includes an additional mandatory third phase, the one defining a reliable causal relationship taking into account a reasonable relationship between, on one side, the qualitative, quantitative and temporal aspects of the specific risk, and, on the other side, the observed "effect". These items must be systematically looked for (unless they are practically unobtainable) if a correct diagnosis of an occupational disease has to be reached.