Although neoplastic changes are the more common cause of basophilia, there are various possible reactive causes (reactive means an elevated basophil count reflecting an immune response of some type). These include:
- Atopy (diseases caused by allergy). Often, basophil counts can be correlated with elevated eosinophil counts. Sometimes, the count can be associated with the severity of symptoms. Basophilia has also been described as being explicitly triggered by an allergy to ragweed.
- Parasitic infection and hypothyroidism have been mentioned as possible causes in textbooks, although various studies do not confirm this.
- In some patients, glucocorticoid therapy can lead to basophilia, which is the opposite of what one would expect.
In our case, the patient is known to have an allergic disease, so #3 cannot be ruled out.
