29. What is allergy? What are the most common allergens? What are the ways of their penetrating into body?
It is an abnormal reaction of the immune system which is characterized by hypersensitivity of an organism to a previously encountered usually harmless substance.
The most common allergens are dust, pollen, mould, animal dander, drugs, food (such as milk, fish, wheat, eggs, fruit, vegetables, peanuts, walnuts, almonds, hazelnuts etc.), insect venom, poison ivy, heat and cold. These allergens can penetrate into our body through: the air (when we inhale it), skin contact and gastrointestinal tract.
30. When does an allergic reaction occur? What is the role of IgE in the allergic reaction? Describe the symptoms of different types of allergic reactions.
It occurs when the body encounters some particle or substance. The specific antibodies produced in all allergic reactions are known as Immunoglobulin E (IgE). These antibodies trigger the release of histamine when exposed to an allergen.
Symptoms vary depending on the type of allergen and location:
An inhaled allergen (such as dust, pollen or mould) can cause: sinus congestion, runny nose, watery, itchy or red eyes, wheezing, sneezing, impaired breathing and asthma.
A contacting allergen (such as animal dander) can cause: itching, rash (or atopic dermatitis, eczema), hives (or urticaria), itchy bumps and swelling.
Food or drugs may cause: abdominal pain, indigestion, swelling, hives, and inability to breath.
Food allergy shouldn’t be confused with food intolerance, which involves only digestive symptoms.
31. How to determine the cause of allergy? What is the treatment for different types of allergy?
Methods of diagnostics:
Taking anamnesis
Skin test – the small amounts of suspected allergen are placed on the skin of the upper arm or back. The skin is scratched to allow entry of the allergen is injected. Swelling and redness at the test site are considered a positive result. Several allergens are usually tested at the same time.
The Radioallergosorbent Test measures the amounts of specific IgE antibodies in the blood stream. The results are not immediately available.
Blood test which may show the high level of eosinophils.
Treatment:
If a food allergy is suspected, one food for a time is eliminated from the diet and then added back to determine if it is triggering the allergic reaction.
Antihistamines are the drugs most often used to control symptoms of allergic reactions.
Symptomatic treatment may be applied. Vasoconstrictors (nasal drops) are used to relieve nasal congestion. Ocular drops are used against red and watery eyes. Topical ointments with corticosteroids relieve itching.
A shot of epinephrine is given in the case of severe allergic reactions.
Corticosteroids are injected to stop severe allergic reactions such as hives, Quincke’s oedema, anaphylactic shock.
Allergy shots or immunotherapy can be administered to eliminate the allergy entirely. In immunotherapy, a small amount of an allergen is injected in order to stimulate the body to produce an antibody to neutralize it. This, in turn, blocks the IgE antibodies from reacting with the allergen and provoking the allergic response.
32. What is anaphylactic shock? Name the first aid measures in case of anaphylactic shock.
Anaphylactic shock is a severe life-threatening allergic reaction. It can be triggered by allergens, such as insect venom, drugs or food. Shock occurs when the allergic reaction triggers the blood vessels to dilate, causing circulatory failure and a drastic drop in blood pressure. In the case of anaphylaxis – epinephrine should be given.