[Eosinophilia in pulmonary infections]

Eosinophilia can be caused by a variety of diseases including allergies, autoimmune diseases, vasculitides, dermatoses, malignancies and drug-induced side effects as well as parasitic and non-parasitic infections. In patients returning from the tropics parasitic infections are the most frequent cause of eosinophilia. The extent of eosinophilia can provide information about the type of pathogen. The diagnostic approach to eosinophilia in travelers returning from the tropics primarily includes three stool examinations for worm eggs and, if necessary, serological tests for helminths. Additionally, a chest x‑ray, an ultrasound of the abdomen and an electrocardiogram (ECG) provide information about organ involvement. Recently, specialized laboratories use molecular techniques (multiplex PCR) to detect worm eggs and intestinal parasites in the stool, which provide a significantly higher sensitivity than traditional stool examination techniques. Cryptococcosis, endemic systemic mycoses (coccidioidomycosis, very rarely histoplasmosis) and invasive mould infections (Aspergillus fumigatus, Mucor spp.) are non-parasitic causes of eosinophilia in blood and bronchoalveolar lavage (BAL).