Can you tell me is there an external allergy test for wheat allergy?

Yes,but: Some allergists will use pin prick testing to define skin sensitivity to a panel of agents, like wheat or beef, etc. They may not be as sensitive as blood tests which are often done at the same time to gain a better understanding of the patients issues. If positive by skin and blood, it would be better documented than by either method done alone and more worth the effort to avoid the food.

Best is two tests: For food allergy, neither the skin test nor the blood test may be sufficient. It seems that the best testing involves both the prick skin test and the blood test. The "golden test" is a double blind food challenge, in which the patient is given wheat hidden in a inert food one time and another time an inert food without wheat; neither the patient nor the physician know which is given.