MCQs In Pediatric Allergy

Q1 :

A 12 year old boy presents with fever, joint aches, and s rash for the past 3 days. He was started on amoxicillin for a site throat a week ago. One of his classmates had a recent diagnosis of strep throat. He has a history of being successfully treated for acute otitis media with amoxicillin a month ago and had been well in the interim. On physical examination, he has swollen lymph nodes, periarticular swelling, and dusky urticaria- like lesions in the skin.

Of the following,these findings are most likely due to :

A- amoxicillin allergy

B- infectious mononucleosis

C- penicillin  allergy

D- scarlet fever

E- serum sickness- like reaction

Answer

E

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This tchild  has the symptoms of a serum sickness–like reaction to amoxicillin. Serum sickness–like reactions typically involve a constellation of signs and symptoms, which can include arthralgias, lymphadenopathy, and urticarial rash with or without fever. Fever, when present, is typically low-grade. Children with serum sickness–like reactions may present with acute onset of joint pain that often leads to inability to walk. The most characteristic rash is an urticarial or serpiginous macular rash that starts in the anterior lower trunk, groin, periumbilical, or axillary regions, and spreads to the back, upper trunk, and extremities. The rash generally lasts a few days to 2 weeks. Ulcers, secondary infection, and scarring do not occur. It has been suggested that the term “serum sickness–like disease” should be replaced by “urticaria with arthritis” to describe this drug-induced syndrome, although this has not become common practice.

In contrast, the cardinal features of classical serum sickness are rash, fever, and polyarthralgia or polyarthritis, which begin 1 to 2 weeks after first exposure to the responsible agent and resolve within a few weeks of discontinuation. Although patients may appear very ill and uncomfortable during the acute febrile stage, the disease is self-limited and prognosis is excellent once the responsible drug is stopped. During classic serum sickness, signs of mild renal dysfunction may be evident; however, renal involvement is unusual in serum sickness–like reactions caused by medications.

Serum sickness may develop more rapidly and severely if a previously immunized patient is reexposed to the culprit antigen. Rather than requiring 7 to 14 days for the development of IgM antibodies, the amnestic IgG response can begin within 12 to 36 hours. Drugs, particularly antibiotics, are the leading cause of serum sickness-like reactions. Penicillin, amoxicillin, cefaclor, and trimethoprim-sulfamethoxazole are most commonly implicated, although many drugs have been associated with these reactions. In children, serum sickness–like reactions are about 15-fold more likely with cefaclor than with other cephalosporins or amoxicillin, even though all are structurally similar ß-lactam antibiotics.

Other drug reactions that may mimic serum sickness or serum sickness–like reactions include nonspecific exanthems, urticaria, and generalized hypersensitivity reactions. The development of an IgE-mediated drug allergy can cause the onset of urticaria during a course of therapy. Other symptoms of Type I, IgE-mediated allergic reactions are pruritus, flushing, angioedema, wheezing, laryngeal edema, abdominal distress with emesis or diarrhea, and hypotension. Symptoms usually appear within minutes to hours of drug administration and then escalate rapidly. This child does not have symptoms of penicillin or amoxicillin IgE-mediated allergy.

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Q 2:

You are seeing a 11- year- old girl for the first time in your practice. She has asthma and has been to the emergency department 3 times in the past month. Your clinics intake procedure include administration of the Pediatric Symptom checklist , a mental and 

Behavioral health screening instrument. The medical student working with you today ask why you are administering a mental health questionnaire for a child who has a chronic illness such asthma.

Of the following, you are Most likely to explain that you use the questionnaire because :

A- children who have chronic illness have an increased risk of anxiety and depression disorders that are often undiagnosed.

B- exacerbations of asthma are usually triggered by anxiety.

C- it is just an office routine; there is no reason to specifically screen for mental or behavioral problems in this patient.

D- most children who have chronic illness will develop a significant psychiatric difficulty.

E- up to 50% of primary care office visits occur because of some type of mental or behavioral health concern.

Answer

A

Children who have chronic illnesses are at an increased risk for emotional and behavioral problems that go undetected. 

A predictive algorithm suggested that 11% of children who have chronic illnesses have probable psychiatric diagnoses, compared to a 5% probability of mental illness among healthy peers.

 Different chronic conditions entail different risks of emotional problems; for instance, asthma, congenital heart disease, and juvenile rheumatoid arthritis are all associated with higher rates of depression and anxiety (up to 1 in 3 patients), but cystic fibrosis is not.



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Q 3:

A 5-year-old boy presents with a history since 2 years of age of coughing, swelling of the lips, mouth, and eyes, and vomiting after ingestion of peanut butter. He has been seen by an allergist in the past. Skin prick testing showed a wheal of 10 mm and a flare of 20 mm to peanut. His reaction to histamine showed a wheal of 7 mm and a flare of 15 mm. He did not react to the negative control. He has been avoiding peanuts and nut products. His mother is worried about risk-taking behaviors in teens and wants to know if her son will outgrow his peanut allergy by the time he is in high school.

Of the following, the BEST information to tell the boy’s mother is that:

A. avoiding soy and other legumes will help him outgrow his peanut allergy

B. daily antihistamine therapy will help him outgrow his peanut allergy

C. he is likely to outgrow his allergy if he strictly avoids peanuts for 3 to 5 years

D. he is unlikely to outgrow his peanut allergy by adolescence

E. you will send him to the allergist for periodic skin testing to see if his reactivity decreases over time


Answer

D

Peanut allergy is usually considered a lifelong food allergy (FA).
 since the child in this vignette had multisystem involvement, it is best to counsel the family to expect likely continuation of peanut allergy into adolescence.

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Q 4:


 A 7-year-old boy who has a 3-year history of asthma is admitted to the hospital for treatment of an acute exacerbation. He has had an upper respiratory tract infection for several days, but he has been afebrile. On physical examination, he exhibits respiratory distress. Auscultation of his chest reveals diffuse wheezing and decreased breath sounds on the right. There is no pneumothorax or pneumomediastinum on chest radiography, but there is atelectasis of the right lung field. He responds to initial therapy, but still has significant wheezing. Except for the upper respiratory tract infection and the asthma exacerbation, he has been in his normal state of health.

Of the following, the BEST intervention for this boy is:

A. bronchoscopy

B. chest physiotherapy

C. intravenous antibiotics

D. N-acetyl cysteine

E. racemic epinephrine

Answer

B

Routine chest radiography is not necessary in most patients who have recurrent wheezing, but asymmetric breath sounds, as described for the child in the vignette, are an indication for radiography. The decreased breath sounds on the right exhibited for this boy suggest the possibility of a pneumothorax or pneumomediastinum. Small areas of atelectasis are common in children who have significant exacerbations of asthma. The atelectasis is due to increased mucous production and mucous plugging, which leads to the collapse of small areas of the affected segment of the lung distal to a mucous plug. Atelectasis occurs frequently during asthma exacerbations and does not require aggressive therapy. Bronchoscopy is unnecessary because the atelectasis resolves in virtually all children.

            Although there is some concern that a severe exacerbation of asthma in children will be worsened by chest physiotherapy, this is the treatment of choice for the child who has atelectasis.

            An intravenous antibiotic is inappropriate for a child who does not have a bacterial infection. N-acetyl cysteine is a mucolytic that may worsen the respiratory symptoms by irritating the airway. Racemic epinephrine is used for the treatment of croup, not for asthma.



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Q 5

A 12-year-old boy presents to the emergency department with a severe asthma exacerbation and respiratory failure. Despite intubation and aggressive resuscitation, he develops severe acidosis, pulmonary edema, and hypoxic encephalopathy. His condition worsens over the next week, and the parents decide to withdraw care. Of the following, the risk factor MOST associated with fatal asthma is

A. Caucasian race
B. high socioeconomic status
C. poor perception of symptoms
D. sensitivity to house dust mites
E. use of daily low-dose inhaled corticosteroids

Answer

C



Risk factors for near-fatal and fatal asthma include marked circadian variation in lung function, male sex, and poor perception of symptoms . Neither daily inhaled corticosteroid use, Caucasian race, nor dust mite sensitivity has been linked to fatal asthma

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Q 6:


A 10-year-old boy presents for evaluation of hives that have occurred daily over the past 4 months. His parents are frustrated by the lack of change in their son’s symptoms despite changing soap, fabric softener, and detergent. They would like to have their son seen by a specialist for more testing. They describe the hives as raised, erythematous, pruritic 1- to 2-cm lesions that involve the trunk and extremities. The hives resolve spontaneously within a few hours and seem to occur at any time of the day or night. The child is otherwise healthy and is only taking an over-the-counter antihistamine to help with itching

Of the following, the MOST likely cause for this child’s hives is

A. allergy to a food additive or preservative
B. allergy to dust mites
C. autoantibody to the immunoglobulin E receptor
D. autoimmune thyroid disease
E. systemic mastocytosis

Answer

C


Chronic urticaria (CU) is defined as recurrent symptoms of pruritic eruptions (urticaria) for more
than 6 weeks, as described for the boy in the vignette. Although the first step is to identify
potential exacerbating triggers, most patients who have CU describe symptoms that occur
regardless of the time of day, foods ingested, or activity level. A specific food or food
additive/preservative may cause urticaria, but that should result in symptoms only shortly after
food ingestion rather than throughout the day and night. Patients who have CU may have
positive skin test results to dust mite and other allergens, but a positive allergy skin test in the
context of CU rarely represents the primary reason for a patient’s symptoms. Because of the
unlikely association of CU with foods or aeroallergens, skin or blood testing for these is not
recommended.

In recent years, up to 30% to 50% of both pediatric and adult cases of CU have been
identified as autoimmune, specifically due to a circulating autoantibody directed against the highaffinity
immunoglobulin (Ig) E receptor (FceRI) located on mast cells and basophils. Activation of
these cells by the autoantibody results in degranulation and histamine release. One diagnostic
test that may help identify affected patients is the autologous serum skin test, which involves an
intradermal injection of autologous serum with a positive and negative control

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Q 7:

A 12-year-old girl presents for a health supervision visit . As you review her medical history, you note that she has marked “penicillin allergy” on the school health form. She remarks that her mother told her she had a rash after amoxicillin when she was 2 years old. Of the following, the BEST statement regarding penicillin drug reactions is that

A. first-generation cephalosporins are less likely to cause a reaction in penicillin-allergic patients
compared with third-generation cephalosporins
B. negative skin testing to major and minor determinants of penicillin can exclude almost all
immunoglobulin (Ig) E-mediated reactions
C. nonpruritic maculopapular rash that occurs in patients who receive amoxicillin during
mononucleosis is a contraindication for future penicillin therapy
D. serum sickness reactions due to penicillin usually are IgE-mediated
E. the incidence of IgE-mediated penicillin allergy among patients who have this history is
greater than 20%

Answer

B

As is often the case, the patient described in the vignette can only recall what her parents
remembered about her drug reaction. Although the incidence of a true immunoglobulin (Ig) Emediated
penicillin allergy is 10% or less in this scenario, most clinicians continue to avoid this
drug class in such patients.

The administration of a penicillin during mononucleosis often results in a nonpruritic, maculopapular rash (Item C143) within a few days. The mechanism for the rashis unknown, but this reaction is not IgE-mediated and should not preclude future penicillin use.

For patients who have experienced a suspected IgE-mediated penicillin reaction, the use of
cephalosporins generally is endorsed for those whose previous reaction did not result in severe
anaphylaxis. Further, the second- and third-generation cephalosporins are less likely to crossreact
with penicillin than are first-generation cephalosporins. Overall, the risk for cross-reaction
remains less than 10% for all cephalosporins

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Q 8:

Which of the following tests is used at home to assess therapy and determine if a patient with asthma should
seek emergency care?

(A) Forced expiratory volume in 1 sec (FEV1)
(B) Forced vital capacity (FVC)
(C) Total lung capacity (TLC)
(D) Peak expiratory fl ow rate (PEFR)
(E) Residual volume (RV)

Answer

D

For home monitoring, PEFR is the best test for assessment of therapy, trigger identifi cation, and the need
for referral to emergency care. It is recommended for patients who have had severe exacerbations of asthma, who are poor perceivers of asthma symptoms, and those with moderate-to-severe disease.