Nut allergies and eating

I don't have personal experience but my son has a nut allergy so I am always aware of foods.
There are areas in France, around the Auvergne, where they use walnut oil frequently. The only area I know of in Spain that may have hidden nuts is Catalunia, they use tiny nuts called pine nuts in some dishes. Across the route of the Frances you really should not have any problem with hidden nut products, not in ordinary restaurants anyway. Beware of fancy ice creams and any bought cakes or sweet dishes as almonds can play a big part but savouries should be fine.

Carry a card, laminated is best, that states in Spanish what exactly you are allergic to and how bad this is (over-exaggerating might be a good idea!) Here a sample text for somebody with walnut allergy:

Tengo una alergia muy grave a nuez. ?Contiene (point finger) nuez?

Hope that helps and Buen Camino! SY