Types of Allergies

Almost every substance is able to induce allergy in predisposed subjects. There are various allergies which infect human beings. Some of the allergies can be categorized and some can not be. Below are the main categories of allergies.

1. Respiratory Allergy
   Respiratory allergies occur around the respiratory tract. Allergens and irritants can both cause respiratory allergy.
   
   
2. Skin Allergy
   Skin allergy can be defined as a reaction which is caused when the skin comes in contact with different substances.
   
   
3. Food Allergy
   A food allergy occurs when your immune system responds defensively to a specific food protein that is not harmful to the body. The first time you eat the offending food, your immune system responds by creating specific disease-fighting antibodies. On having the food again, antibodies spring into action, releasing large amounts of histamine in an effort to expel the foreign invader from your body. These are powerful chemical that can affect the respiratory system, gastrointestinal tract, skin or cardiovascular system.
   
   
4. Chemical Sensitivity
   It is a condition in which various symptoms reportedly appear after a person has been exposed to any or a wide range of chemicals. The exposure may occur as a major event, such as a chemical spill, or from long-term contact with low-levels of chemicals, such as in an office with poor ventilation. As a result of exposure, people with may develop sensitivity and have reactions to the chemicals even at levels most people can tolerate.
   
   
5. Other Allergy
   There are some allergies which are present which cannot be categorized under a particular allergy or symptom, such as plant allergies, allergy during pregnancy, a reaction caused due the use of a drug, migraine - a headache which is more severe in nature and an allergy which is caused due to a insect bite.