Welcome, and thank you for putting your trust in me!

Although it is conceivable that you have developed an allergy to your dentures (the acrylic material of which most dentures are composed is a known allergen), allergic reactions don't typically occur a full three years after denture placement, because most of the free monomer-- the volatile component which is the usual offender-- would long ago have dissipated.

Your symptoms would most likely fall into one of two categories:

1-there may be a mechanical irritation of the denture base due to some discrepancy in the fit between the denture base and your gums, or an issue with the way your bite was designed, or...
2-you may have developed a mucocutaneous condition which may or may not be related to the denture itself.

Neither of these issues fall within the scope of expertise of most medical doctors, including ENT specialists, and your problem lies most properly in the dental realm. Sadly, the emphasis on full denture prosthesis has of late been under-emphasized within the dental profession due to the current fashionability of implants, and you may need to seek specialty care for an effective assessment of your denture's biomechanics. For this purpose, you should seek consultation with a prosthodontist, whose specific skill set is more properly suited to matters like yours. You can find contact information for a prosthodontist by consulting the online directory of the American Board of Prosthodontics.

In the event that your prosthodontist determines that your symptoms derive from a mucous membrane disorder rather than mechanical irritation, you should then consult with a clinical oral pathologist, whose training and experience deals specifically with these issues. To find an oral pathologist in your community, consult the online directory of the American Academy of Oral & Maxillofacial Pathology.

Hope this helps...