This claim is false. Dairy does not cause severe asthma, but if you have a dairy allergy, it can trigger symptoms similar to asthma (Healthline). Healthline also says that both asthma and food allergies trigger the same reactions because "the immune system goes into overdrive because it mistakes a food or other allergen as an attacker." It releases chemicals to protect your body from substances like pollen or nuts, causing symptoms like wheezing, coughing, runny nose, and shortness of breath (WebMD). This is called allergic asthma, or allergy-induced asthma.