raremaprare-disease reference indexOrphadata 2026-06-23 · HPO 2026-09-01
ORPHA:251332

Unexplained long-lasting fever/inflammatory syndrome

Synonyms: Persistent fever/inflammation of unknown origin

Type
Disease
Group
Disorder
Age of onset
All ages
Status
active

A rare systemic disease characterized by febrile illness (body temperature >38.3°C on several occasions) or inflammation (elevated serum C-reactive protein and erythrocyte sedimentation rate) lasting at least three weeks and for which no specific diagnosis is achieved despite extended diagnostics.

1

Names in Orphadata languages

12 of 12 languages
LangNameSynonyms
enUnexplained long-lasting fever/inflammatory syndromePersistent fever/inflammation of unknown origin
frSyndrome inflammatoire/fièvre de longue durée inexpliquéeFièvre/inflammation prolongée d'origine indéterminée
deFieber-Syndrom, langanhaltendes unerklärbaresPersistierendes Fieber/Anhaltende Inflammation unbekannter Ursache
esFiebre inexplicada de larga duración/síndrome inflamatorioFiebre persistente/inflamación de origen desconocido
itSindrome infiammatoria/febbre di lunga durata ad eziologia non nota
nlOnverklaarbare langdurige koorts/inflammatoir syndroomPersisterende koorts/inflammatie van ongekende oorsprong
ptSíndrome inflamatório/febre de longa duração, não explicado
plNiewyjaśniona długotrwała gorączka/zespół zapalny= en
csSyndrom nevysvětlitelné dlouhotrvající horečky či zánětu= en
ukНезрозуміла тривала лихоманка/запальний синдромСтійка лихоманка/запалення невідомого походження
zh原因不明的长期发热/炎症综合征原因不明的持续发热/炎症综合征
trAçıklanamayan uzun süreli ateş / inflamatuar sendromKalıcı ateş / kaynağı bilinmeyen inflamasyon

Definition in:

2

Cross-references

qualifier = Orphanet mapping relation
SourceCodeQualifierICD relationValidation
ICD-10R50.8NTBTattributedvalidated
ICD-11MG26NTBTattributedvalidated
MONDO0016666Evalidated
UMLSC5679630Evalidated

E exact · NTBT this ORPHAcode is narrower than the target · BTNT broader than the target · ND not decided.

3

Classification

Preferential parent (Orphanet linearisation):

Parents in the classifications (2):

No children.

4

Genes

0 direct

Orphanet records no gene directly on this code.

5

Prevalence and incidence

0 records

No prevalence record in this release.

6

HPO phenotypes

Orphanet has no HPO annotation for this code in this release.

7

Sources for this card