Allergies are particularly unique in the medical field because they differ between patients. An allergy is a specific immunological reaction to a normally harmless substance, which does not bother most people. Allergy sufferers are often sensitive to many substances. Common allergens that cause allergic reactions include seasonal outdoor allergens such as pollen from trees, grass and weeds, and year-round indoor allergens including dust particles, animal dander and indoor mold. Most people can usually be cured with various treatments. Many people are curious about why they are allergic and others are not. The answer to this question is that allergies are genetic in almost all cases. Scientists and researchers believe that people inherit a tendency to be allergic, although not to any specific allergen. Children are much more likely to develop allergies if their parents are allergic. Interestingly, people with perennial (perennial) allergies commonly develop the problem as adults and are more likely to be women than men. Symptoms may decrease as you age, but rarely go away completely without treatment. Patients who usually suffer from allergies suffer from many symptoms due to allergic reactions. Normally, your immune system protects you from invading agents such as bacteria and viruses. Otherwise, harmless allergens (substances that cause allergies) cause the body to react as if they were dangerous invaders. In fact, your immune system is responding to a false alarm. Some of the common allergens that disrupt the immune system are pet dander, mold, and dust mites. When you first come into contact with these allergens, your immune system treats the allergen as an invader and mounts an attack. The immune system does this by generating large amounts of a type of antibody (a disease-fighting protein) specific to the particular allergen you are allergic to. In the case of pollen allergy, the antibody is specific to each type of pollen: one antibody may be produced to react against oak pollen and another against ragweed pollen. This antibody attaches to certain cells in your body. The next time you come into contact with the allergen, the allergen sticks to the antibody like a key inserted into a lock, causing the release of powerful inflammatory chemicals, including histamine. These chemicals travel to various parts of the body, such as the respiratory system, to cause allergy symptoms including runny nose, itchy eyes, and sneezing, among others. Patients suffering from allergies usually have some serious disadvantages. Allergy patients usually have difficulty sleeping, breathing, and sometimes even eating or drinking, depending on the allergy.