Asthma Treatment with Inhaled Steroids: Daily or On Demand (PRN)?

Please note that the discussion below applies only to mild asthma.

For mild persistent asthma:

Although the IMPACT and BEST studies suggest that on-demand therapy in some patients with mild persistent asthma achieves a similar degree of asthma control based on symptoms and functional outcomes, the IMPACT study indicates that regular and on-demand therapy is not equivalent for controlling airway inflammation.

For mild intermittent asthma:

On-demand treatment with SABAs as suggested by the international guidelines is a reasonable option. Alternatively, courses of anti-inflammatory drugs for asthma (e.g. low-dose ICS, LTRAs) can be prescribed to subgroups of patients with intermittent asthma including those with seasonal allergic asthma or perennial allergic asthma exposed to triggering factors (e.g. cold, upper respiratory tract infections) also considering the good tolerability of these drugs.

Asthma classification and treatment for each stage (click to enlarge the image).

References:
Pharmacotherapy of Asthma: Regular Treatment or On Demand? Medscape.
http://www.medscape.com/viewarticle/714427

Should patients with mild asthma use inhaled steroids? CCJM, 2010.

Image source: Symbicort Turbuhalers, Wikipedia, public domain.