I think eosinophils are related to allergies. It would suggest you are currently having some sort of allergic reaction (seasonal allergies?).
In addition to allergies, eosinophil can be a sign of inflammation and/or infection. Were you sick just before or when you had your blood tested? Do you have allergies? High inflammation levels?
I've had high eos levels for a decade now, although the percentage varies depending on what else is going on in my life. None of my docs has been intensely concerned about it, although my immunologist was most curious about it.
There is at least one rare disease that the eos cells attack the body. The one I'm familiar with is a gastrointestinal disease, which they do biopsies of the lining of your stomach and small intestine to see if the eos cells are clustered there. But it's apparently really really rare, and like Steph said, high eos levels are usually due to allergies.
I also always have the same problem, having high density of eos in my blood. This time the report has come with 23%. And the report always comes with a high percentage whenever I am prescribed for a blood test out of high fever or throat infection. Eventually it comes down after taking anti biotic, but again after sometimes I discover the same.
My doctor says that its due to allergy. I do have allergy towards dust and might be pollens. I had a breathing problem in childhood. But now I dont have any. Now a days I am having congestion between my throat and nose. I always try to cough out the discomfort and I get yellow phlegm regularly. I guess I am going through some infections.
My mother has also the same problem, and we discovered after sometime that she has developed a heart condition where water gets clogged in her heart.
Am I susepetible for the same? Kindly anyone advice