Joshua is a 10-year-old boy who has had asthma since the age of 5. Despite his use of inhaled corticosteroids (ICS), Joshua suffers from nocturnal coughing and is fatigued during physical exercise.

Joshua is compliant with his ICS regimen and uses the correct inhalation technique.
His FENO value is 8 ppb.

Questions:
• Does Joshua have (allergic) asthma or should another diagnosis be considered?
• In what way is the FENO value informative?
The FENO value shows that he does not have an ongoing eosinophilic inflammation (i.e. not allergic asthma).

Actions:
Discontinue the steroids, as a patient with a low FENO value is not likely to respond to an increased dose of steroids.
Another cause for the symptoms should be considered. Possible explanations might include non-allergic asthma (no-eosinophils), gastrointestinal reflux, post nasal drip, nervous hyperventilation, rhinitis, or sinusitis.
Measure FENO values after two to four weeks without steroids (in keeping with NHLBI guidelines, which recommend more frequent monitoring of patients requiring additional supervision).

On the next visit after 4 weeks:
Joshua’s FENO value was 10 ppb. There was no need for steroids as his FENO value did not significantly change after the ICS were discontinued.
An investigation revealed that Joshua’s symptoms were caused by sinusitis, which was treated using appropriate medication.
Immunoglobulin E (IgE) tests were negative, indicating that he is non-atopic. His steroids could be withdrawn without any recurrence of his previous airway symptoms.