http://hl7.org/fhir/StructureDefinition/allergyintolerance-duration|4.0.1

The amount of time that the Adverse Reaction persisted.
typedestination
baseDefinitionhttp://hl7.org/fhir/StructureDefinition/Extension
typehttp://hl7.org/fhir/StructureDefinition/Extension
Extension.value[x].typehttp://hl7.org/fhir/StructureDefinition/Duration