My dad experiences a severe sinus headache/ migraine (along with sinus pressure), and nausea at least once a week after exposure to dust. He owns and manages a retail store so exposure to dust is inevitable. It is so bad that he spends the entire day in bed, sometimes the next day too. He's been to a specialist and had tests done, but they could not find anything wrong with him. He has also been to an allergy doctor who confirmed that he has a dust allergy. Upon the doctor's recommendation, he had allergy shots for eighteen months (the kind where you inject some of what you are allergic to into your blood), changed the bedding to hypoallergenic bedding, and a whole bunch of other things, but there still isn't any improvement. He used to take Benadryl Sinus or Claratin D, or Tylenol and it helped, but now they make him very nauseous.

Does anyone have any ideas what could be wrong with him? Or what medication he could take? Any suggestions would be extremely helpful. Thank you!

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