Other allergy, initial encounter

This code signifies an allergic reaction that doesn't fit into more specific allergy categories, such as food, drug, or contact allergies. It represents an adverse immune response to an unspecified or unusual allergen, manifesting with various symptoms.

Use this code when a patient presents with an allergic reaction to an unknown substance, or to an allergen not covered by more specific ICD-10-CM codes. This is appropriate for the initial evaluation and treatment of such an allergic episode.

• Ensure documentation clearly states the allergic nature of the reaction, even if the specific allergen is unknown.
• Avoid using this code if a more specific allergy code (e.g., food, drug, contact dermatitis) can be assigned.
• Remember the "X" placeholder and "A" for initial encounter; subsequent encounters would use "D" or "S".