Can a dust mite allergy be causing me to loose my sense of smell?

Probably not. Loss of smell is usually due to a benign growth called nasal polyps. Chronic sinus infection sometimes is the cause. A skull fracture is a rare cause. For help see an otolaryngologist or an allergist.
Not likely. Severe allergies may cause much nasal congestion/symptoms and thus can reduce your sense of smell. So, typical sniffle from allergies due to dust mite should not cause loss of sense of smell...Check wtih your doc.
Yes. The most common type of allergic reaction to aerosolized particles is respiratory including nasal, sinuses, and bronchial inflammation as in asthma. Chronic nasal congestion will make your mucosa thick and the nerve endings of the roof of the nose that transmit smell to the brain will not have adequate exposure to the air.
Possibly. Loss of the sense of sense is typically due to severe acute or chronic inflammation. However, trauma, surgery or some , medications can cause one to lose the sense of smell. Anosmia, or the loss of sense of smell, should be evaluated by your physician and if needed an allergist.