Eosinophils are circular granulocytes involved in host defence against parasites and primarily allergic reactions. This article explains the causes and presents a case study of tropical eosinophilia.

Development of Eosinophils

Eosinophils develop in the bone marrow and migrate from blood to target tissues. They are present in the blood, lung, thymus, uterus, mammary glands, spleen, and gut. It has the capacity to antigen t cells It moves to the inflamed area and has antiparasite and antibacterial activity, particularly in allergic reactions and modulates inflammation.

Causes of Eosinophilia

Causes of eosinophilia include:

• Drugs as anticonvulsants, NSAIDs, antineoplastics
• Helmithes infestation microfilaria
• Acute and chronic eosinophilic pneumonia

The case

This case had a patient performing a night service; upon examination, the patient's blood film revealed microfilaria. His cough had become more severe during the night-it was dry. 

Diagnosis

1. On examination, the chest rhonchi X-ray showed increased vascular markings and diffused interstitial lesions.
2. Total WBC was 15600 N =55%, L=20%, E=20%, M=5%.
3. IgE was more than 1000.

Conclusion

In endemic zones, tropical pulmonary eosinophilia should be considered as one of the causes of dry cough as it simulates asthma and microfilaria is not always detected.

Hence, indirect tests such as Elisa and microfilaria antibody detection, raised igE level with response to DEC treatment give a clue to diagnosis, and the relapse is less.

 Disclaimer- The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.

About the author of this article: Dr Mahendra Sharma is a practising pulmonologist from Daudnagar.