Allergen
* ALL allergens are immunogens.
* Many allergens can cause anaphylaxis.
* More allergens mean more asthmatic symptoms and breathing problems.
* Most allergen causes reaction
  - releases into air
  - triggers allergic reaction
* Most allergens are airborne and seasonal
  - irritate from inhalation, but few are contact types, such as an allergy to wool
  - resist stomach acids and digestive enzymes
* Some allergen affects humans.
* Some allergen causes death
  - respiratory difficulty
* Some allergen includes food
  - milk
* Some allergen interferes with digestion
  - protein digestion
  - allergens affect mast cells directly, aggravating the itch
* Some allergens are easy to identify because the reaction is immediate
  - present only during certain seasons for example, ragweed in the fall
  - cause a reaction when inhaled
* are everywhere, indoors and out
  - generally very small particles
  - materials such as pollen, pet dander, foods, or dust, that cause allergic responses
  - microscopic particles that are inhaled through the nose and mouth
* are more subtle trigger factors
  - tolerable without drugs or saline sprays
  - normally harmless substances that most bodies ignore
  - one type of trigger for people who are asthmatic
  - proteins that cause a sensitivity reaction in tissues upon contact
* are substances that cause allergic reactions and trigger asthma symptoms in some people
  - an allergic response in certain sensitive people
  - trigger allergic reactions
  - to which one has become allergic eg. nickel, perfume, rubber
  - the substances that can trigger an allergic reaction
* are the substances that cause allergic illnesses
* are things such as pollen, feathers, dust, foods, animal fur and medicines
  - which trigger allergies in people
  - usually animal or vegetable proteins from foods, pollens, or pets
* associates with asthma.
* bind to specific IgE on surface of mast cells in respiratory tissue.
* can be in the dander or fur of many animals and in the proteins of their saliva
  - behave in much the same way as pirates invading a ship
* can cause severe allergic reactions in some individuals
  - skin rashes, nausea, and respiratory problems
* can enter the body through the skin, the nose or by the mouth in food
  - when they're eaten, touched, inhaled or breathed in
  - include pollen, dust mites, food, medications and insect venoms
  - make someone itchy, and then they scratch, and then it gets worse and worse
* cause others.
* causes immediate reaction
* enter the body in one of three ways.
* stress the adrenal glands and stimulate excess insulin production.
* tend to be protein molecules.

### allergen:

Airborne allergen
* are also the frequent culprits that trigger the symptoms of asthma.
* can include pollens, molds, dust mites, cockroaches, and animal dander.

Common allergen
* Some common allergen includes food
  - allergens are pollen, animal dander, mites, many foods, house dust and feathers
* are dairy products, eggs, and wheat
  - dust mites, proteins from pet fur called dander, molds, and pollen
* are pollen, dust mites, animal dander, and mold
  - foods, dust, molds, venoms, fur, and medications
  - pollens, household dust, molds, domestic animal dander, smoke, and some foods

Different allergen
* affect different people.
* are more prevalent in different parts of the country or the world.

Food allergen
* Some food allergen includes food
* are naturally-occurring proteins that exist in the foods
  - typically nuts, seeds, shellfish, or dairy products
  - usually proteins
* create inflammation.
* have small molecular weights, which allows absorption through the lung or gut lining.

Indoor allergen
* Some indoor allergens are also difficult to avoid, but they can be reduced.
* can also cause allergic rhinitis.

Seasonal allergen
* abound, as well.
* are for the most part found outdoors.