AllergyIntolerance

The AllergyIntolerance resource records allergies and adverse reactions to substances, medications, food, and other agents. This is critical for patient safety.

API convention: the patient reference is sent as a flat string id field (patientId). encounterId is optional for the recording context. All resource ids are raw UUIDs (v4).

Creating an Allergy Record

curl -X POST https://api.esus.health/fhir/AllergyIntolerance \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -H "Content-Type: application/fhir+json" \
  -d '{
    "patientId": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
    "clinicalStatus": {
      "coding": [{
        "system": "http://terminology.hl7.org/CodeSystem/allergyintolerance-clinical",
        "code": "active",
        "display": "Active"
      }]
    },
    "verificationStatus": {
      "coding": [{ "code": "confirmed", "display": "Confirmed" }]
    },
    "type": "allergy",
    "category": ["medication"],
    "criticality": "high",
    "code": {
      "coding": [{
        "system": "http://snomed.info/sct",
        "code": "387458008",
        "display": "Penicillin"
      }]
    },
    "reaction": [
      {
        "manifestation": [
          { "coding": [{ "code": "271807003", "display": "Urticaria" }] }
        ],
        "severity": "severe"
      }
    ]
  }'

The code field is optional — for verbal allergy history without a coded substance, the record can be created with reaction.manifestation alone.

Clinical Status

Code	Description
`active`	Currently affecting the patient
`inactive`	No longer active
`resolved`	Previously existed, now resolved

Criticality

Level	Meaning
`low`	Low risk if exposed
`high`	High risk if exposed
`unable-to-assess`	Cannot be determined

Reaction Details

Each entry in reaction[] can additionally include:

Field	Description
`substance`	The specific agent that triggered this reaction (CodeableConcept)
`exposureRoute`	How the patient was exposed (oral, topical, etc.)
`severity`	`mild`, `moderate`, or `severe`

Why It Matters

Allergy information must be easily accessible to all care providers. Many medical errors occur when allergy information is not adequately communicated.