[Eosinophilia - inflammation, proliferation, reaction. Part 1: diagnostics]

Eosinophilia presents a challenge to differential diagnostics due to the multitude of possible causes. An initial difficulty is often to distinguish between threatening disease symptoms and relatively harmless secondary reactions. A highly dynamic clinical progression with severe impairment of the vital functions, like breathing, for example, can make swift action necessary. An example of this is known as acute eosinophile pneumonia, which can often only be controlled with the rapid use of high steroid doses. However, a peripheral blood eosinophilia must not lead to an automatic use of steroids before the most important core tests, as this can compromise further diagnostic measures. Furthermore, less dramatic courses require careful handling of an eosinophilia. Various pneumological, infectological, rheumatological or haematological / oncological disease patterns with a prolonged course can develop seriously if they are not recognised in time and treated in a targeted manner. There is no guideline for eosinophile clinical pictures in general. Already the recommendations for a structured diagnosis are scarce and are often concentrated on internist emphases.