<StructureDefinition xmlns="http://hl7.org/fhir">
  <meta>
    <lastUpdated value="2021-02-18T10:41:44.785+00:00" />
  </meta>
  <url value="http://example.org/fhir/StructureDefinition/DerivedAllergy" />
  <name value="DerivedAllergy" />
  <status value="draft" />
  <fhirVersion value="4.0.1" />
  <kind value="resource" />
  <abstract value="false" />
  <type value="Allergy" />
  <baseDefinition value="http://example.org/fhir/StructureDefinition/Allergy" />
  <derivation value="constraint" />
  <differential>
    <element id="Allergy.onsetDate">
      <path value="Allergy.onsetDate" />
      <min value="1" />
    </element>
  </differential>
</StructureDefinition>