neutropenia?

I have a 6.5 year old Pit Bull mix who just had some bloodwork drawn at her regular checkup.  Both this bloodtest, and the one she had a year ago, show low neutrophils.  When we got that result a year ago, we dismissed it as an anomaly, maybe the tail end of an infection.  However, now getting the same result a year later, we're taking it seriously.  All the rest of her results are normal.  No fever.  She's in good apparent overall health.  She does have joint problems (which is why the yearly checkups) - luxating patellas, rotated tibia, a loose/malformed ankle joint, and mild HD, which she was born with.  She has localized demodex as a puppy, which cleared up on it's own in about a year.  The last few months, there's been increased panting, which we attributed to discomfort from her knees when she's "overdone it".  She's still eating well, although somewhat less enthusiastically than usual.  Not lethargic.  No fever.

The vet is getting advice from the specialist on what route to take with testing.

What I'm wondering is, could the low neutrophils just be her "normal", and not clinically significant?

[Aleda M Cheng, D.V.M., C.V.A]

Neutropenia, all by itself with no other symptoms may or may not be significant.

Neutropenia can be immune-mediated (your dog's immune system directed against her own neutrophils)  which is considered a primary disorder,  or the neutropenia may occur secondary to infection, neoplasia (cancer), or the side effects of certain drugs that your dog may have been on.  The most common infectious causes of neutropenia are Ehrlichiosis (a tick borne disease), parvovirus, or, systemic mycosis or fungal infections(histoplasmosis, cryptococcosis).

If it is primary, immune mediated neutropenia, it should be responsive to steroids therapy.  Blood and other tests should be able to identify Ehrlichiosis, histoplasmosis, parvo, neoplasms, etc.