Any food that YOU are sensitive to can cause acne. Quinoa seems like a strange suspect. Is up new to your diet?

You may or may not be sensitive to quinoa. Personally I am not sensitive to quinoa as I tested myself: http://www.acne.org/messageboard/topic/353197-food-that-causes-acne/

Suggest you do what competent Doctors and Dermatologists have recommended for decades. (I am an old guy).

Pick a food you want to test.
Do not eat that food for two or three weeks.
Then eat a lot of the food you are testing for four days.

You will know if that food causes acne.

This is a slow test, as you can only test one item at a time.

In the case quinoa, mix quinoa flour with water, and make pancakes. Eat the pancakes with nothing on the pancakes, and do this for four days. You will know after four days if quinoa causes you acne, or not.

You need to do the same test for any food you suspect as causing you acne: dairy, nightshade plants, citrus, soy etc.

Pancakes cause acne. Lol.

If it's something you're sensitive to, absolutely. Have you eaten it before or is it new to your diet? Another thing to consider, if you're female, is where you are in your cycle. I know I've thought food was making me break out, only to realize I was a few days away from starting my period.