A person who has lived in regions endemic for various parasites may develop a marked eosinophilia with pulmonary symptoms.


Clinical findings:

(1) history of living in a tropical, subtropical or warm temperate region

(2) cough

(3) breathlessness

(4) wheezing

(5) pulmonary infiltrates on chest X-ray

(6) reduced vital capacity and FEV1


Severe, persistent disease can result in pulmonary hypertension and cor pulmonale.


Laboratory findings:

(1) marked peripheral eosinophilia

(2) elevated serum histamine

(3) elevated serum histaminase

(4) elevated serum IgE

(5) increased eosinophils in bronchial alveolar lavage

(6) elevated erythrocyte sedimentation rate


Many cases are due to microfilaria lodged in small pulmonary arteries but other parasites can also give rise to the syndrome. A positive response to therapy with diethylcarbamazine is supportive evidence for the diagnosis of filariasis.


The differential diagnosis includes other causes of marked eosinophilia (allergies, tumors, eosinophilic leukemia).


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