Lupin isn't just a professor in a J.K. Rolling novel, or an absolutely beautiful flower. It is a generally harmless food that can trigger allergies in some people. It is now being used more in the United States as an ingredient in gluten-free foods.
We've discussed lupin (a legume) here in 2012 and a Norwegian study conducted earlier that year (read more). While the FDA has its list of top 8 allerges, European countries have their list of top allergens as well, and Lupin is one of the them. But now, it is showing up in gluten-free foods in the United States. The FDA has issued a warning for those with legume and peanut allergies to include lupin in your label reading. It might be wise to discuss with your doctor/allergist and include it also in your allergen testing.
Here is one of the articles from Prevention Magazine: http://www.prevention.com/food/healthy-eating-tips/fda-warns-about-lupin-allergy-gluten-free-foods
Read more about Lupin: Those with PEANUT ALLERGIES CAN CROSS REACT to FENUGREEK & LUPIN