From the Guidelines
Mild thrombocytosis and eosinophilia can occur together due to several underlying causes, and the most common causes include infections, inflammatory conditions, allergic reactions, and hematologic disorders. When evaluating a patient with these laboratory abnormalities, a thorough history and physical examination are essential, focusing on recent infections, medication use, travel history, and symptoms of underlying inflammatory or malignant conditions. The diagnostic workup may include:
- Stool examination for parasites
- Inflammatory markers (ESR, CRP)
- Chest imaging
- Bone marrow examination to rule out hematologic malignancies The treatment should target the underlying cause rather than the laboratory abnormalities themselves, such as antiparasitic medications for helminth infections, discontinuation of offending drugs, or specific therapy for inflammatory conditions, as suggested by 1. It is also important to consider the possibility of secondary (reactive) eosinophilia, which can be caused by a wide range of nonneoplastic or neoplastic conditions, as noted in 1. Additionally, the presence of eosinophilia can be associated with significant end-organ damage, particularly affecting the heart, lungs, and central nervous system, as highlighted in 1. Therefore, it is crucial to identify and address the underlying cause of mild thrombocytosis and eosinophilia to prevent long-term health problems and improve patient outcomes. Some specific conditions that may cause mild thrombocytosis and eosinophilia include:
- Helminth infections, such as Strongyloides stercoralis, as mentioned in 1
- Inflammatory bowel disease, rheumatoid arthritis, or vasculitis, as suggested by 1
- Allergic reactions, such as allergic asthma or atopic dermatitis, as noted in 1
- Hematologic disorders, such as myeloproliferative neoplasms, as discussed in 1 and 1
- Certain medications, such as antibiotics or NSAIDs, as mentioned in 1.
From the Research
Causes of Mild Thrombocytosis
- Thrombocytosis can be caused by various factors, including iron deficiency anemia, active malignancy, chronic inflammatory disease, and splenectomy 2, 3, 4
- Iron deficiency anemia is a common cause of reactive thrombocytosis, and iron replacement therapy can help resolve the condition 3, 4, 5
Relationship between Iron Deficiency and Thrombocytosis
- Some studies suggest that iron deficiency is associated with an increased risk of thromboembolism, particularly in patients with inflammatory bowel diseases, chronic kidney disease, or cancer 3
- However, other studies have found no significant correlation between serum ferritin levels and platelet counts in healthy blood donors 6
Eosinophilia
- There is limited evidence in the provided studies to suggest a direct link between the causes of mild thrombocytosis and eosinophilia
- Further research is needed to fully understand the relationship between these two conditions
Clinical Implications
- A practical approach to investigating patients with persistent thrombocytosis based on clinical characteristics, such as active malignancy, chronic inflammatory disease, splenectomy, and iron deficiency, may assist in accurately identifying patients more likely to have secondary causes of thrombocytosis 2
- Iron supplementation therapy can be an effective preventive strategy in reducing the risk of thromboembolism in patients with iron deficiency anemia 3, 5