Actually, they do. This is due to the placebo effect that accounts for around 30% of the improvement with any positive thing we do to improve our health. So even though physicians tell you not to expect measurable improvement for 1-2 weeks you may subjectively feel better very soon. Nothing wrong with that. You'll feel even better in a few weeks when the anti-inflammatory effects of the inhaled steroid kicks in.
No. Steroid inhalers are the foundation of therapy for recurrent, persistent asthma (occurring more than 2 days per week or 2 nights per month). It targets the inflammation in the airways which can actually eventually damage the tissue. Treatment with inhaled steroids helps patients maintain their lung function.But they do not provide immediate relief of symptoms.
No... Steroid inhalers do not have an effect fast enough to use them acutely. Steroid inhalers have a prolonged effect over time so they need to be inhaled even when you are symptom-free, as a maintainence therapy. Take your inhalers as prescribed by your doctor to hopefully avoid acute exacerbations.