Eosinophilic lung diseases

Eosinophils are a type of white blood cell. Excess eosinophils (eosinophilia) are generally associated with allergy or are a response to infestations with parasites. The effects may involve the airways, producing asthma or allergic bronchopulmonary aspergillosis (see above). It may also involve the gas-exchanging alveoli (as in simple pulmonary eosinophilia, infection with parasites, drug-induced or eosinophilic pneumonia) or even the lung vessels (Churg Strauss syndrome).

This type of lung disease is rare in childhood, except when caused by parasites. Usually the diagnosis is made by detecting too many eosinophils in the blood and seeing shadows on Chest X-ray (due to collections of eosinophils in the lungs). The most common parasites to be associated with this problem are Ascaris lumbricolides, Toxocaria canis and Filaria. The larvae (immature forms of the parasites) migrate through the lungs. Sudden onset or gradually developing symptoms of breathlessness, wheeze, cough or fever may occur. In cases caused by parasites, liver, spleen and lymph nodes may also enlarge.