Can cats become allergic to cat litter?

Yes, cats can be allergic to any number of ingredients of cat food. Some but not all could be: Wheat Gluten and/or Brewer's Yeast. Some might have a food sensitivity to dairy or tuna. An example of sensitivity would be vomiting everytime they eat a certain food. For Allergies an example would be brewer's yeast causing a cat to itch a lot. Wheat Gluten allergy might cause diarrhea.