Sake, also known as nihonshu, can best be compared to beer. It is a Japanese alcoholic beverage made from fermented rice.
If you have a rice allergy, you are likely to notice similar symptoms when you eat cooked or steamed rice, or when eating rice noodles.
It may be possible that alcohol makes you more sensitive to your allergens. Therefore, while you may not have a problem with rice on its own, you may have a noticeable problem when you have rice together with alcohol.
After the sake fermentation process is complete, the resulting liquid is full of rice solids, and is very clouded. Other than nigori, the product is filtered and ends up being quite clear. You may therefore have bigger problems with nigori and other types of sake.