Immunology Questions and Answers – Allergy – Type I Hypersensitivity Reaction

This set of Immunology Multiple Choice Questions & Answers (MCQs) focuses on “Allergy – Type I Hypersensitivity Reaction”.

1. Which of the following is termed as type 1 hypersensitivity? 
a) Cytotoxic reactions
b) Immune complex reaction
c) Immediate hypersensitivity
d) Cell mediated
View Answer

Answer: c
Explanation: When our body responds to the foreign substances (also known as certain types of allergens) in an overstated way which might have a positive or negative impact on our immunity, we say that the hypersensitivity mechanism is in the action. This reaction usually occurs when the normal body circumstances fail to respond and act against the allergens. There are majorly 4 types of hypersensitivity reactions- out of which type 1 hypersensitivity is known for its immediate response where the mechanisms take place instantly hence it is termed as Immediate hypersensitivity.  

2. Which of the following is NOT a type of allergic conjunctivitis?
a) Simple allergic conjunctivitis
b) Vernal keratoconjunctivitis
c) Non-atopic keratoconjunctivitis
d) Giant papillary conjunctivitis
View Answer

Answer: c
Explanation: There are 4 main subtypes of allergic conjunctivitis. These include: 1) Simple allergic conjunctivitis (SAC) comprising both seasonal and perennial allergic conjunctivitis, 2) Vernal keratoconjunctivitis (VKC), 3) Atopic keratoconjunctivitis (AKC) and 4) Giant papillary conjunctivitis (GPC). Allergic conjunctivitis refers to the process by which the conjunctiva becomes inflamed due to allergic reactions, also known as hypersensitivity reactions. It is mainly allergic hence it is categorised under Type 1 Hypersensitivity Reactions. 

3. Type 1 hypersensitivity is accompanied by which of the following reasons?
a) Increase in basophils
b) Decrease in eosinophils
c) Increase in neutrophils
d) Increase in eosinophils
View Answer

Answer: d
Explanation: According to the research study, it is assumed that type 1 hypersensitivity is accompanied by an increase in eosinophil number along with differential count of peripheral white blood cells (WBCs). In addition, the serum named tryptase may also be increased during mast cell activation. 

4. Systemic anaphylaxis and Local anaphylaxis are two types of anaphylaxis which is considered to be a type 1 hypersensitivity reaction.
a) True 
b) False
View Answer

Answer: a
Explanation: Anaphylaxis is an allergic condition which can be caused due to several factors like food, medications or even venoms and bee stings. This is a subtype of type 1 hypersensitivity reaction. The most common factors can sometimes prove harmful to us if our immunity becomes weak due to secondary supporting illnesses and disorders. Bee sting is one of the most common factors to look at as majority of anaphylaxis cases occur due to it. It is true that there are two major types of anaphylaxis which include systemic and local anaphylaxis. Systemic type of anaphylaxis occurs within minutes with the symptoms of asthma, diarrhoea and shock. On the other hand, local anaphylaxis can cause fever as well as asthma in almost 10% of the people that have atopy. 

5. Type 1 hypersensitivity occurs mainly due to action of which immunoglobulin?
a) IgA
b) IgE
c) IgD
d) IgM
View Answer

Answer: b
Explanation: IgE antibody isotype molecules are bound to receptors on mast cells as well as basophils. When there is a cross-linking mechanism between IgE antibody isotype molecules, the degranulation mechanism gets triggered. This takes place as a clinical response of type 1 hypersensitivity which usually takes place after vaccine dosage supervision is attempted successfully. 

6. Which of the following is a class of bronchodilator (B2 receptor agonist) used as a medicine for treatment of asthma?
a) Brondecon
b) Theodur
c) Vetolin
d) Atrovent
View Answer

Answer: c
Explanation: There are several types of medication used for treatment of asthma like relievers, preventers and symptom controllers. Reliever medications are taken when an asthma attack happens as well as before exercise to prevent attacks in those suffering from exercise-induced asthma. Pharmacological classes of bronchodilator include medications like B2 receptor agonists, Ipratropium bromide and Methylxanthines out of which Vetolin is a type of B2 receptor agonist, Brondecon and Theodur comes under Methylxanthines and Atrovent is a type of Ipratropium bromide.

7. Allergic rhinitis is associated with which part of the body?
a) Eyes
b) Skin
c) Soft tissue
d) Nose
View Answer

Answer: d
Explanation: Allergic rhinitis is an allergic disease categorized under type 1 hypersensitivity which affects many people worldwide. Rhinitis means ‘inflammation of the nose’. Hence it is associated with the nose. It is also termed as perennial in cases when symptoms are present throughout the year and it is termed as seasonal when symptoms are mainly seen during weather changes. 

8. Which of the following is NOT the most commonly used treatment for diagnosing type 1 hypersensitivity?
a) Mast cell stabilizers
b) Immunotherapies
c) Steroids
d) Antihistamines
View Answer

Answer: b
Explanation: There is actually no permanent cure for treating type 1 hypersensitivity reactions. The treatments are done so as to maintain its control only. Some of the most commonly used methods and medications are: 1) mast cell stabilizers as mast cell (a type of white blood cell) plays a major role in allergic reactions, the aim of these drugs is to block the action of mast cells. 2) steroids which can directly be applied on site of involvement in case of skin allergies or can be consumed. 3) antihistamines can also be taken by mouth or if it is in the form of cream/oil, it can be applied directly on skin (in case of skin allergies). On the other hand, immunotherapy is not commonly used for maintaining the control of the spread of type 1 hypersensitivity reactions. 

9. Allergens are presented to T cells by which type of cell/receptor during sensitization phase of type 1 hypersensitivity?
a) TCR (T cell receptor)
b) BCR (B cell receptor)
c) APC (antigen presenting cells)
d) B cells
View Answer

Answer: c
Explanation: Allergens are also termed as antigens as these are the foreign invaders in our body. Antigen presenting cells (APCs) help in controlling and presenting these allergens to T cells during type I hypersensitivity, specifically in the sensitization phase. As and when these APCs pass on the allergens to T cells, they further get activated to cause stimulation of B cells in order to produce IgE antibodies. 

10. Which of the following allergic reaction is associated with soft tissue?
a) Allergic rhinitis
b) Allergic conjunctiva
c) Angioedema
d) Asthma
View Answer

Answer: c
Explanation: Allergic reaction associated with soft tissue is known as angioedema. This is a type of reaction which causes swelling of the skin or mucosal tissues. These tissues are termed as soft tissues which can be easily damaged. These tissues are most commonly present in the nasal passage. If the tissue damage gets through deeper tissues, it can lead to breathing issues or airway obstruction. 

11. Which of the following is NOT a symptom of perennial allergic rhinitis?
a) Runny nose
b) Nasal blockage
c) Lung failure
d) Decreased sense of smell
View Answer

Answer: c
Explanation: Perennial allergic rhinitis is a type of allergic rhinitis associated with the nose. It generally causes inflammations in nose. Perennial, by the name itself suggest that this type of allergic rhinitis is present all through the year (I.e., full time allergy). The most common symptoms of this type of allergy is runny nose, sneezing or blockage of nasal passage. It may be complicated by sinusitis, resulting in facial pain and localized headaches. 

12. What is the term used for genetic tendency to develop classic allergic diseases?
a) Genotropy
b) Atopy
c) Homotopy
d) Entropy
View Answer

Answer: b
Explanation: Atopy is defined as genetic tendency to develop classic allergic diseases.most of the times Atopy and Allergy are interchangeable but still are different in terms of effects. Atopy is one of the major risk factors of anaphylaxis. The other risk factors include age, gender and exposure. Anaphylaxis is a sudden, severe allergic reaction to a substance (called an allergen) that can be life-threatening. Common substances which can cause as severe allergic reaction include bee stings, insect bites, peanuts, eggs, drugs given to the body, etc.

13. Which are the two types of angioedema?
a) Hereditary and Systemic
b) Hereditary and Acquired
c) Systemic and Acquired
d) Systemic and Conditional
View Answer

Answer: b
Explanation: Angioedema is comprised of two major types – hereditary and acquired. Hereditary, by the name itself suggests that this type of angioedema can be associated with the patient since birth due to any genetical errors or issues that has come by the parents. As a result, hereditary angioedema can be caused passed on from parents to offsprings. On the other hand, acquired angioedema refers to angioedema caused by the surrounding external factors like harmful rays of sun, chemical interference with the body or any other factor that is not healthy for inhalation and exposure.  

14. Which test is used to identify the type of allergy that a patient suffers?
a) Skin prick test
b) Blood test
c) Urine test
d) Stress test
View Answer

Answer: a
Explanation: Once a patient is allergic to a substance, the best way to treat it is to avoid what he/she is allergic to. For this, a skin-prick test is done which checks the allergic reactions to as many as 50 different substances at once. This test is also called as puncture or scratch test. This test identifies allergies to pollen, mold, dust mites and certain food. 

15. Which of the following is NOT a type of asthma?
a) Atopic asthma
b) Non-atopic asthma
c) Drug-induced asthma
d) Genetic asthma
View Answer

Answer: d
Explanation: Asthma is mainly divided into four groups as follows: 1) Atopic asthma: This is the most common type of asthma. Patients usually have relatives who have atopic asthma, and themselves experience other allergic diseases like food allergy. House dust mites (HDM), pollen and animal fur are common triggers. 2) Non-atopic asthma: This type is triggered by respiratory infections in patients without a family history or other allergic traits. 3) Drug-induced asthma: Aspirin medication can sometimes induce asthma attacks. 4) Occupational asthma: This type of asthma can be caused if the human is exposed to harmful fumes of chemicals.

16. Which of the following is NOT a common antigen that causes angioedema?
a) Animal protein 
b) Food items like nuts and eggs
c) Insect stings
d) Opiates
View Answer

Answer: d
Explanation: Angioedema is a type I hypersensitivity reaction. Type I hypersensitivity is characterized by IgE mediated reaction. IgE is a specific type of antibody that helps to fight infection, but also responsible for this type of allergic response. The most common antigens that trigger the dysfunction of IgE are animal protein, food like eggs, fish, milk and insect stings. On the other hand, Opiates is a type of drug which is used against Angioedema. Opiates include morphine and oxycodone and these are used as strong pain killers. 

17. What does RAST stand for?
a) Radio antigen sorbent testing
b) Radio allergo sorbet test
c) Radio allergo sorbent testing
d) Radio antigen sorbet test
View Answer

Answer: c
Explanation: Radio Allergo Sorbent Testing (RAST) is similar to the skin prick test but is more expensive. This test is suggested by doctors only when the skin prick test fails to give accurate results or is not suitable for the particular body type. This test is mostly preferred if a patient is at high risk from Anaphylaxis. In this test various allergens are exposed to blood samples that is taken from the patient and the levels of IgE produced are measured. 

18. Eczema, asthma and allergic rhinitis is triggered most commonly by which of the following factor?
a) House dust mite
b) Insects 
c) Mud
d) Water borne particles
View Answer

Answer: a
Explanation: House dust mite is a common allergen and there is no easy way of removing it. People with allergic disease (such as asthma, eczema and allergic rhinitis) can be easily triggered by house dust mite. The most common source of these mites is the bedding. For this, sheets of the bed must be washed and cleaned weekly in hot water. Covering the mattresses, pillow and quilts by dust mite resistant cover can also be very helpful. 

19. Which part of any plant/grass can cause allergies?
a) Pollen
b) Petals
c) Stem
d) Petiole
View Answer

Answer: a
Explanation: Pollen is the main source from the nature to be the reason for causing any type of allergy. There are various ways in which we can come in contact with pollen. Some of the common ways are as follows: 1) Thunderstorms can cause bursts of increased pollen counts, when starch granules are released from pollen that are small enough to breathe in, triggering asthma. 2) Pollen can be blown for long distances on windy days. Sources of pollen are usually grass or trees that are not flowering. 

20. Which of the following type 1 hypersensitivity causes redness of eyes?
a) Allergic asthma
b) Cataract
c) Starabismus
d) Allergic conjunctivitis
View Answer

Answer: d
Explanation: Conjunctivitis is a very common cause for an uncomfortable, red eye. There are a number of causes for conjunctivitis, which include bacteria, viruses and, importantly, allergies. Allergic conjunctivitis affects the conjunctiva of the eye. The conjunctiva refers to the thin, mucous membrane that extends from the limbus of the eye over the anterior surface of the eyeball and then continues over to cover the posterior surface of the eyelids. It occurs if there has been any recent exposure to other people with conjunctivitis or an upper respiratory tract infection. This may be a sign of viral conjunctivitis and is seen more commonly. 

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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