> ## Documentation Index
> Fetch the complete documentation index at: https://docs.metriport.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Allergy Intolerance Reaction

> Schema documentation for the Allergy Intolerance Reaction table in the Metriport data model

The `allergy_intolerance_reaction` table records individual reactions that have occurred for an allergy/intolerance. Each allergy/intolerance can have multiple reactions.

**Primary Keys:**

* allergy\_intolerance\_reaction\_id

**Foreign Keys:**

* allergy\_intolerance\_id - links to the [allergy intolerance](/medical-api/handling-data/schema-v000/allergy-intolerance/base) table

| Column                             | Data Type | Description                                                                                                                                                                                                                          |
| ---------------------------------- | --------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| allergy\_intolerance\_reaction\_id | varchar   | Unique identifier for the allergy intolerance reaction                                                                                                                                                                               |
| allergy\_intolerance\_id           | varchar   | Unique identifier for the allergy intolerance                                                                                                                                                                                        |
| snomed\_code                       | varchar   | SNOMED CT code for the specific substance or pharmaceutical product considered to be responsible for event                                                                                                                           |
| snomed\_display                    | varchar   | Human-readable description of SNOMED CT code                                                                                                                                                                                         |
| source\_substance\_code            | varchar   | Original code of the specific substance or pharmaceutical product considered to be responsible for event                                                                                                                             |
| source\_substance\_display         | varchar   | Original display of the specific substance or pharmaceutical product considered to be responsible for event                                                                                                                          |
| source\_substance\_system          | varchar   | Original system of the specific substance or pharmaceutical product considered to be responsible for event                                                                                                                           |
| onset\_date                        | datetime  | Date when the allergy/intolerance reaction began                                                                                                                                                                                     |
| severity                           | varchar   | Severity of the reaction. Possible values:<br />– <code>mild</code>: The reaction is mild in nature.<br />– <code>moderate</code>: The reaction is moderate in nature.<br />– <code>severe</code>: The reaction is severe in nature. |

**Related Tables:**

* [Allergy Intolerance Reaction Manifestation](/medical-api/handling-data/schema-v000/allergy-intolerance/reaction-manifestation) - Records of specific manifestations of this reaction