Rare diseases · Sign or symptom
CSF pleocytosis
HP:0012229
What it means
An increased white blood cell count in the cerebrospinal fluid.
Rare diseases that can present with this25
Very common80–99%
5Common30–79%
9- Acute transverse myelitis
- Autoimmune limbic encephalitis
- Familial hemophagocytic lymphohistiocytosis
- Familial or sporadic hemiplegic migraine
- Japanese encephalitis
- New-onset refractory status epilepticus
- Paraneoplastic cerebellar degeneration
- Primary angiitis of the central nervous system
- Secondary syringomyelia
Sometimes5–29%
10- Acquired hemophagocytic lymphohistiocytosis associated with malignant disease
- Bickerstaff brainstem encephalitis
- Coccidioidomycosis
- Congenital syphilis
- Hemophagocytic syndrome associated with an infection
- Hereditary cerebral amyloid angiopathy
- Miller Fisher syndrome
- Neuromyelitis optica spectrum disorder
and 2 more in this range
The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Also called: Cerebrospinal fluid pleocytosis · Increased leukocyte count in CSF
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Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.