PatientAllergy

A documented allergy or intolerance to a substance that causes adverse reactions in a patient. Critical for patient safety during medication prescribing, surgical procedures, and dietary planning.

Overview

PatientAllergy records a patient's adverse reactions to specific substances, capturing the allergen, reaction severity, symptoms, and verification status. This information is essential for clinical decision support systems that alert providers to potential allergic reactions before prescribing medications or performing procedures. The entity supports both true allergies (immune-mediated) and intolerances (non-immune adverse reactions).

Key Concepts

Allergen and Reaction Type

Each allergy record links to:

• allergen - The specific substance via PatientAllergen (e.g., penicillin, peanuts, latex)
• reactionType - Whether it's an allergy or intolerance via PatientReactionType

Allergy vs Intolerance

• Allergy: Immune system response (can be life-threatening)
• Intolerance: Non-immune adverse reaction (uncomfortable but not dangerous)

Severity Assessment

The severity field via HealthReferenceSeverity indicates the danger level:

Clinical Manifestations

The manifestations array documents observed symptoms:

Skin Reactions

• Rash, hives, itching
• Facial swelling, angioedema

Respiratory

• Difficulty breathing, wheezing
• Throat tightness, stridor

Systemic

• Anaphylaxis
• Hypotension, shock

Gastrointestinal

• Nausea, vomiting
• Abdominal pain, diarrhea

Status Tracking

Two status fields track the allergy state:

status via PatientAllergyStatus:

• Active - Currently a concern
• Inactive - No longer relevant
• Resolved - Patient has outgrown the allergy

verificationStatus:

• unconfirmed - Reported but not clinically verified
• confirmed - Verified through testing or documented reaction
• refuted - Testing proved no allergy exists

Information Source

The reportedBy field tracks who provided the allergy information:

• patient - Self-reported by the patient
• family-member - Reported by relative (important for pediatrics)
• healthcare-professional - Documented by provider
• previous-provider - From transferred medical records
• other - Other sources

Timeline

• onsetDate - When the allergy was first discovered
• lastOccurrence - Most recent allergic reaction (helps assess current risk)

Use Cases

Medication Safety Check

Before prescribing:

1. Query active, confirmed allergies for patient
2. Check if medication class matches any allergen
3. Display warning with severity and manifestations
4. Require acknowledgment for override
5. Document reason if proceeding despite allergy

Emergency Department Triage

When patient arrives:

1. Pull allergy list prominently in chart
2. Flag life-threatening allergies with visual alerts
3. Ensure wristband includes critical allergies
4. Alert team before any medication administration

Allergy Documentation

When recording new allergy:

1. Select allergen from PatientAllergen catalog
2. Document reaction type and severity
3. Record specific manifestations observed
4. Set verificationStatus based on evidence
5. Note who reported the allergy

Allergy Verification

When confirming suspected allergy:

1. Review unconfirmed allergies
2. Order allergy testing if appropriate
3. Update verificationStatus based on results
4. Change to refuted if tests negative
5. Upgrade severity if confirmed and severe

Care Coordination

When transferring patient care:

1. Export complete allergy list
2. Include severity, manifestations, and notes
3. Flag any life-threatening allergies
4. Ensure receiving provider acknowledges review

Related Entities

Enums

verificationStatus

reportedBy