J45.21
BillableMild intermittent asthma with (acute) exacerbation
HCC Category Mapping
RxHCCHCC 229 — COPD and Chronic Bronchitis
0.000What This Code Means
Asthma that occurs occasionally with mild symptoms, but the patient is currently experiencing a sudden worsening with increased breathing difficulty.
Coding Tips
- •Document the baseline asthma severity (mild intermittent) and confirm acute exacerbation is present
- •Exacerbation indicates acute worsening requiring treatment adjustment; do not confuse with status asthmaticus
Clinical Significance
Mild intermittent asthma with acute exacerbation indicates a patient with baseline mild intermittent asthma who is experiencing a significant worsening of symptoms beyond their normal variation. Acute exacerbations require escalation of treatment and may lead to emergency department visits or hospitalization even in patients with mild baseline disease.
Documentation Requirements
- ✓Established diagnosis of mild intermittent asthma
- ✓Clear documentation of acute exacerbation: increased wheeze, dyspnea, cough, or chest tightness beyond baseline
- ✓Provider language indicating acute worsening: 'exacerbation,' 'flare,' 'acute attack,' 'worsening asthma'
- ✓Treatment escalation: systemic corticosteroids, nebulizer treatments, increased rescue inhaler use
- ✓Peak flow or spirometry measurements during the exacerbation if available
- ✓Trigger identified if applicable (viral infection, allergen exposure, etc.)
Commonly Confused Codes
J45.20 — Mild intermittent asthma, uncomplicated: use for stable baseline disease, not during an exacerbationJ45.22 — Mild intermittent asthma with status asthmaticus: use for severe, life-threatening attack not responding to treatmentJ45.901 — Unspecified asthma with acute exacerbation: less specific; prefer severity-classified codesJ45.31 — Mild persistent asthma with acute exacerbation: use when baseline severity is persistent (symptoms >2 days/week)
Code Hierarchy
└J45Asthma└J45.2Mild intermittent asthma└J45.21Mild intermittent asthma with (acute) exacerbation
└J45.21Mild intermittent asthma with (acute) exacerbation