Anaphyl reaction due to shellfish (crustaceans), sequela

This code describes the long-term effects or complications arising from a past anaphylactic reaction specifically triggered by shellfish, such as shrimp, crab, or lobster. It indicates that the acute allergic episode has resolved, but the patient continues to experience residual symptoms or conditions directly attributable to that severe allergic event.

Use this code when documenting a patient presenting with a chronic condition or persistent symptom that is a direct consequence of a previously experienced anaphylactic reaction to shellfish. This applies to situations where the initial acute reaction has passed, but its lasting impact on the patient's health is being addressed.

• Always ensure documentation clearly links the current sequela to a past anaphylactic reaction caused by shellfish.
• Do not use this code for the acute anaphylactic reaction itself; use the appropriate acute code (e.g., T78.02XA) for the initial episode.
• A seventh character of 'S' (sequela) is mandatory for this code, indicating a late effect.