Chronic headaches, migraines, attention deficit disorder, nasal congestion, runny nose, chronic, frequent colds, chronic urticaria of unknown cause, chronic acne, diarrhea, irritable bowel syndrome, colitis, constipation, heartburn, excessive gas in the stomach, easy weight gain. These may be signs that you are suffering from an allergy to something. But how do we know what is causing the allergy? Therefore, allergy testing is important to find out the cause of the risk of which allergens.