The body's immune system is responsible for detecting foreign elements that enter the body and are there before responsible for the different types of allergies that some people have. An allergy is the immune system's overreaction to a certain foreign substance known as an allergen. It is referred to as an overreaction because the immune system attacks these allergy-causing substances which are actually harmless unlike other foreign elements that bring diseases and harm to the body. Having an allergy is actually a defense mechanism of the body to prevent further entry of the allergen into the body.

The different types of allergies are dependent on the type of allergen that caused it. Allergens can be anything from the environment. The popular ones are pollen, dust mites, animal fur and dander, foods, medicines and insect stings. There are also some uncommon allergens like cigarette smoke, latex, mold, etc. Hay fever is one of the types of allergies that are caused by pollen grains and some substances. Others simply call this pollen allergy. Hay fever in the spring is associated with tree pollen allergies. In the summer, having hay fever may be due to weed and grass pollen. The pollen inhaled by a person is considered as invasive elements. Special cells called the mast cells release histamine and some leukotriene which cause inflammation of the nasal passages, sinuses and eyelids. A person having hay fever may also experience sneezing.

One of the types of allergies that are becoming more prevalent today is food allergy. The most common food allergy is peanut allergy. This type may be moderate to extremely severe allergies. Sometimes, people who are allergic to peanuts also show sensitivity to other tree nuts such as pecans, walnuts and pistachios. Egg allergies are also common in children but can be outgrown ever. Egg allergies are associated with the proteins present in the white part of the egg. Another common food allergy is shellfish or other seafood allergy. However, it is important to note whether the occurring symptoms are due to food allergy or food intolerance. This can be determined upon consulting a physician.

It is also important to notice sensitivity to medications and drugs, may it be an allergic reaction or not. Unexpected reactions to medications are alarming and can lead to serious complications when not given attention. Penicillin and sulfa drugs are some of the medications that cause an allergic reaction to many people. Patients with penicillin allergies are treated with other antibiotics. A true allergy to medications is characterized by a rash, itchy throat, difficulty of breathing or anaphylaxis. Symptoms that are not allergic in nature may just be a side effect of the medicine. Caution should be observed especially when taking a certain drug for the first time. Any unusual effects must be taken into account and reported to a physician to know whether an allergic reaction is taking place or not.

It is important to identify the different types of allergies a person may have. By knowing the specific type, a person may distinguish what substances or objects to avoid so that an allergic reaction can be prevented. Avoiding the allergen is usually the main treatment for allergies. Also, knowing the different types of allergies enabling the physician to come up with the right management and medication to relieve discomfort resulting from the symptoms accompanying the allergy.