I'm allergic to
Use this if you are female. In Spanish, adjectives must match the gender of the person.
A very common alternative, literally 'I have an allergy to'. Works for any gender.
Use this to say something 'gives you an allergy'. Example: 'El maní me da alergia' (Peanuts give me an allergy).
A simple, direct way to state a food restriction: 'I can't eat...'. Highly practical in restaurants.
I'm allergic to peanuts. Does this dessert have peanuts?
Just to let you know: my daughter is allergic to tree nuts.
I have an allergy to shellfish. What do you recommend?
I can't eat gluten. Do you have gluten-free options?
The phrases 'Soy alérgico/a a' and 'Tengo alergia a' are standard and universally understood in all Spanish-speaking countries, including Spain, Mexico, Colombia, and Argentina.
While the phrase is the same, the pronunciation of 'Soy' may sound more like 'shoy' due to the regional accent ('yeísmo rehilado'), but the meaning is identical.
Using 'estoy' instead of 'soy'. For example: 'Estoy alérgico a...' (Incorrect). — An allergy is considered a permanent or long-term characteristic, so you must use the verb 'ser' (soy), not 'estar' (estoy). 'Estoy' is for temporary states or locations.
Forgetting gender agreement. A female speaker saying: 'Soy alérgico' (Incorrect). — Adjectives in Spanish must match the gender of the noun they describe. If you are female, you must say 'Soy alérgica'.
Omitting the preposition 'a'. For example: 'Tengo alergia los mariscos' (Incorrect). — You must include the preposition 'a' (to) after 'alérgico' or 'alergia'. The correct phrase is 'Tengo alergia a los mariscos'.
Confusing 'maní' and 'nueces'. — 'Maní' specifically means peanut (it's technically a legume). 'Nueces' is the general term for tree nuts (walnuts, almonds, etc.). Be specific for safety.