Primary Care Coding Alert

Question: What is the ICD-9 code for mild, intermittent asthma?

Kansas Subscriber

Answer: ICD-9 does not include a specific code for mild, intermittent asthma. Rather, asthma is broadly classified under 493.x with several subclassifications:

• 493.0x -- Extrinsic asthma

• 493.1x -- Intrinsic asthma

• 493.2x -- Chronic obstructive asthma

• 493.8x -- Other forms of specified asthma

• 493.9x -- Asthma, unspecified.

Codes 493.0x and 493.1x imply the existence of specific etiologies (causes) for the asthma. For example, extrinsic asthma is commonly due to allergic reactions and often occurs in children while intrinsic asthma commonly occurs in adults due to reasons other than allergies (for instance respiratory infections, chemical inhalation, smoking, etc.). Code 493.2x implies a prolonged duration of the disease and 493.8x classifies the remaining types of asthma that are specified, meaning exercised-induced (493.81) and cough variants (493.82). Finally, 493.9x is for cases of asthma that are unspecified.

For the diagnosis of mild, intermittent asthma, this can be considered unspecified as we cannot discern the etiology nor the duration of the disease from the diagnosis. In this particular instance, we therefore use this code: 493. 92 (Asthma, unspecified; with [acute] exacerbation).