If I suffer from allergies and asthma, could I be at risk of getting acute sinusitis?

Not really... Acute sinusitis is due to an infection of your sinuses and your risk for this is not increased by the presence of asthma. However, if you get acute sinusitis, this could lead to an asthma exacerbation so see your doctor for treatment if you develop symptoms of acute sinusitis.
Yes. Most sinusitis are related to prolonged nasal congestion . Thus you will need to control the nasal congestion in order to reduce the risk of sinusitis. Although sinusitis may aggravate asthma, it is not caused by it.
Yes it often. Occurs with the other two ... But not always. Best thing is to find out what causes your allergies (?Pets, dust , pollen etc. ) and avoid as best as possible. Your allergist can give you a nasal spray to keep your passages open and avoid sinus issues. Www. Acaai .Org.
Yes. Yes, for two reasons: allergic inflammation in the sinuses increases blood flow, so bacteria in the sinuses are better able to get the nutrients they need to grow. Second, sinus health is all about drainage - and the inflammation of allergies causes swelling that impairs drainage. Add the inflammation of a viral or bacterial infection, and the drain openings swell shut -> acute sinusitis.
Possibly. Your allegies may cause edema and swelling of the mucus membranes causing inflammed sinuses.