An increase in eosinophil granulocyte is known as eosinophilia.

Granulocytosis can be a feature of a number of diseases:

- Infection, especially bacterial

- Malignancy, most notably leukemia (it is the main feature of chronic myelogenous leukemia, CML)

- Autoimmune disease

In cardiovascular disease, increased white blood cell counts have been shown to indicate a worse prognosis.

As mentioned above, symptomatic features of paraneoplastic syndrome cultivate in four different ways: endocrine, neurological, mucocutaneous, and hematological. The most common presentation is a fever (release of endogenous pyrogens often related to lymphokines or tissue pyrogens), but the overall picture will often include several clinical cases observed which may specifically simulate more common benign conditions.

The following diseases manifest by means of neurological dysfunction: Lambert-Eaton myasthenic syndrome, paraneoplastic cerebellar degeneration, encephalomyelitis, limbic encephalitis, brainstem encephalitis, opsoclonus myoclonus ataxia syndrome, anti-NMDA receptor encephalitis, and polymyositis.