Allergies Flashcards
What are allergies?
Anallergyis a disease in which the immune system makes aninflammatory responseto a harmlessantigen.
Define allergen.
Any antigen that causes an allergy
How do allergens enter the body?
Allergens may be inhaled or ingested, or they may come into contact with the skin.
Symptoms of pollen allergy:
sneezing, a runny nose, nasal congestion and itchy, wateryeyes.
Examples of allergy causes:
Inhaling ragweed pollen may cause coughing and sneezing.
Skin contact with oils in poison ivy may cause an itchy rash
Whats the severity of allergies:
The symptoms of allergies can range from mild to severe.
How can mild allergies be treated?
Mild allergy symptoms are often treated withantihistamines.
Define anaphylaxis:
The most severe allergic reaction
This is a life-threatening response caused by a massive release of histamines.
How can anaphylaxis (sever allergic reaction) be treated?
It requires emergency medical treatment.
Whats a type 1 reaction?
Type I reactions are mediated by proteins called IgE antibodies produced by the immune system. These are produced in response to the allergens such as pollen, animal dander or dust mites, or even certain foods. This causes the release of histamine and other chemicals causing inflammation and swelling
Examples of type Iallergicreactions include:
bronchialasthma, allergic rhinitis, allergicdermatitis, food allergies, allergic conjunctivitis(eye inflammation) and anaphylaxis(allergicshock).
Symptoms of anaphylaxis:
People with anaphylaxis have extreme difficulty inbreathing, swelling,low blood pressure, bluish skin and shock.
Whats a Type II or cytotoxic reaction?
This type of allergic reaction is mediated by proteins called IgG and IgM antibodies. The antibodies involved in type II reaction damage cells by activating a component of immunity called the complement system.
When might type 2 allergic reactions be seen?
Type IIallergicreactionscan be seen in certain conditions like
autoimmune hemolyticanemia,
immunethrombocytopeniaand
autoimmuneneutropenia.
Whats Type III or immunocomplex reactions:
Type III reactions are also mediated by proteins i.e. IgM and IgG antibodies. These antibodies react with the allergen to form immunocomplexes (antigen-antibody complexes). These complexes are responsible for the reaction.
