Wright stained PBS showing eosinophilia

Wright stained PBS showing eosinophilia as shown above image due to a condition of having an increased number of eosinophils in the peripheral blood. Leukocytes are an essential component of the cellular immune system. Eosinophils are specific white blood cells that are a normal part of the cellular immune system, play a role in normal physiologic processes and host defense, and participate in allergic reactions and the defense against parasitic infections. Eosinophilia is said to occur when there are greater than 500 eosinophils per microliter or cubic millimeter, though the exact cutoff varies by the laboratory. Eosinophilia can be considered mild, moderate, or severe. Usually, less than 5% of the circulating leukocytes in a person are eosinophils.

Causes of Eosinophilia 

Causes  of eosinophilia range from less serious but very common conditions such as nasal allergy and asthma to more serious hematologic conditions, including:

• Allergies and asthma
• Drug allergy
• Infections (mostly from parasites)
• Autoimmune disease
• Blood disorders and cancers
• Endocrine disorders
• Diseases involving organs and systems, including the:
  • Skin
  • Lungs
  • Gastrointestinal system
  • Neurological system
  • Joints, muscles, and connective tissue
  • Heart

Eosinophilic disorders are often called by names that reflect where the problem is located. These include:

• Eosinophilic cystitis, a disorder of the bladder
• Eosinophilic fasciitis, a disorder of the fascia, or the connective tissue throughout the body
• Eosinophilic pneumonia, a disorder of the lungs
• Eosinophilic colitis, a disorder of the colon (large intestine)
• Eosinophilic esophagitis, a disorder of the esophagus
• Eosinophilic gastritis, a disorder of the stomach
• Eosinophilic gastroenteritis, a disorder of both the stomach and the small intestine

Bibliography

1. Textbook of Medical Laboratory Technology-Godkar P. B.
2. Textbook of Pathology by Harsh Mohan-7th Edition
3. Textbook of Pathology with Clinical Applications-Stanley Leonard Robbins
4. https://my.clevelandclinic.org/health/diseases/17710-eosinophilia
5. Textbook of Medical Laboratory Technology-Ramnik Sood
6. Textbook of Pathophysiology: Basic Mechanisms of Disease-Stjepan Gamulin, Matko Marusic, Zdenko Kovac