For people with allergies and asthma, sometimes the very air they breathe can be bad for their health. That’s because a variety of pollutants in our air -- collectively called smog -- can aggravate asthma and allergy symptoms, leaving people with these conditions struggling to breathe.
Decongestants make some people feel jittery or have trouble sleeping. If that happens, cut back on caffeine while taking them. If that doesn't help, you may need to stop taking them. Nasal sprays are less likely to cause these problems and may be a short-term solution.