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Start free with EleplanFamilial hemophagocytic lymphohistiocytosis
ORPHA:540Disease
Also called Familial HLH
What it is
Familial Hemophagocytic lymphohistiocytosis (FHL) is a rare primary immunodeficiency characterized by a macrophage activation syndrome with an onset usually occurring within a few months or less common several years after birth.
Key facts
- Prevalence
- 1-9 / 100 000 (at birth, Sweden)
- Age of onset
- Adolescent, Infancy
- Inheritance
- Autosomal recessive
- Classified as
- Disease
Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.
Signs and symptoms
Very common80–99%
12- Abnormality of multiple cell lineages in the bone marrow
- Abnormality of serum cytokine level
- Abnormality of tumor necrosis factor secretion
- Anemia
- Elevated circulating hepatic transaminase concentration
- Fever
- Hemophagocytosis
- Hypoalbuminemia
- Immune dysregulation
- Increased circulating ferritin concentration
- Increased serum interferon-gamma level
- Thrombocytopenia
Common30–79%
20- Abnormality of the coagulation cascade
- Abnormality of the respiratory system
- Abnormal natural killer cell physiology
- Abnormal renal physiology
- Abnormal skin morphology
- Cholestatic liver disease
- CSF pleocytosis
- Decreased liver function
- Decreased total neutrophil count
- Ecchymosis
- Erythroderma
- Hepatomegaly
- Hypertriglyceridemia
- Hypofibrinogenemia
- Increased circulating interleukin 6 concentration
- Lymphadenopathy
- Petechiae
- Purpura
- Skin rash
- Splenomegaly
These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.
Genes
ICD-10 codes
ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.
Cross-references
Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.
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