Other allergy, sequela

This code signifies a residual or late effect of an allergic reaction that is not otherwise specified. It is used when the acute allergic event has resolved, but the patient continues to experience symptoms or conditions directly attributable to that past allergic response.

Apply this code when documenting a patient presenting with chronic or persistent issues stemming from a prior, unspecified allergic reaction. Examples include long-term dermatological changes, respiratory sensitivities, or gastrointestinal disturbances that are clearly linked to a past allergic episode. This code is appropriate when the specific allergen or the exact nature of the initial allergic reaction is not precisely categorized elsewhere.

• Always sequence this code after the code for the specific sequela or chronic condition being treated.
• Ensure documentation clearly links the current condition to a past allergic event.
• Avoid using this code for acute allergic reactions; those require codes from the T78.0-T78.4 series without the "S" seventh character.