Having an allergy means the body overreacts to usually harmless substances. Usually, the immune system's job is to protect the body from bacteria and viruses. Allergies begin if the body reacts too much to allergens that trigger the immune system, triggering an allergic react to harmless substances, because it "thinks" the substances are harmful.
There are different forms of allergies that the body can develop throughout the whole life, such as food allergies, pollen and pet allergies, skin allergies etc. If the immune system overreacts to one of these substances, it releases histamine, which results in swelling and inflammation. This leads to typical allergic reactions like runny nose, itchy eyes and sneezing.
Allergic asthma is a more serious form of these overreactions of the immune system. The body reacts hyper-sensibly to an allergen, the muscles around the airways tighten, and the respiratory tract becomes inflamed and loaded with mucus. The result is coughing, wheezing, tightening of the chest, shortness of breath or rapid breathing.
Ayurveda, over 5000 years in practice, provides a range of herbal products that not only treat the symptoms of allergies and allergic asthma, but helps cure the disease.