Hi..
Can understand your concern..
As per your complain a dark blue patch over the upper palate can be due to either an
allergic reaction or an injury caused due to some hard food like hard chips,due to injury to some minor salivary glands causing a small pseudocyst known as
Mucocele, it can also be a
PURPURA which is caused due to inflammation of blood vessel, or a
Hemangioma caused due to growth of cells of lining of blood vessel etc..
I would suggest you to consult an oral pathologist and get evaluated for the exact cause of the patch and get necessary investigations done and treatment will be planned accordingly..
In case of allergic reaction after removal of stimulants it will resolve itself..
Also mucocele and hemangioma are also self healing and get resolved over the time..
Purpura can occurs which may or may not be due to
platelet disorders and treatment will be planned according to the diagnosis..
Hope this information helps..
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Thanks and regards..
Dr.Honey Nandwani Arora.