LE 4 (INFECTIOUS/ ALLERGY) 2026 Flashcards
Each of the following statements about measles is TRUE, EXCEPT:
A. Koplik spots appear 1 to 4 days before the onset of rash
B. The peak of contagiousness occurs during the rash, which lasts for 7–10 days
C. The patient is infectious both before and after the appearance of the rash
D. Both active and passive immunization can help prevent measles
Which of the following statements about congenital rubella syndrome (CRS) is NOT true?
A. It is diagnosed if the infant has IgM antibodies at birth
B. It can be diagnosed if IgG antibodies persist beyond 6 months of age
C. Infection after 16 weeks of gestation commonly results in major congenital anomalies
D. CRS is associated with sensorineural deafness, cataracts, and congenital heart disease
Which of the following statements about Herpes Simplex Virus (HSV) is CORRECT?
A. Most neonatal herpes is caused by HSV type 1
B. Primary HSV infection in infants usually leads to fever lasting 4–9 days
C. HSV type 1 is the most common cause of herpes labialis
D. HSV type 2 can be treated effectively with immunoglobulin
A 4-year-old child is diagnosed with varicella (chickenpox). The child’s aunt is pregnant, and the family is asking when it is safe for the child to be around her.
Question:
When is the earliest it is safe for this child to meet his pregnant aunt?
A. As soon as the fever resolves
B. When the vesicles begin to crust over
C. Once all lesions are fully crusted
D. Two weeks after the rash first appears
What should be given if a newborn presents with cicatricial scarring?
A. Acyclovir
B. Varicella vaccine
C. Intravenous immunoglobulin
D. Varicella-zoster immune globulin (VZIG)
A young child develops high intermittent fever for 3–5 days. When the fever subsides, a rash suddenly appears on the trunk and then spreads to the face and extremities. The child is otherwise well-appearing.
Question:
Which virus is most likely responsible for this clinical picture?
A. Human herpesvirus 6 (HHV-6)
B. Parvovirus B19
C. Rubella virus
D. Coxsackievirus A16
An 18-month-old child presents with hemolytic anemia, thrombocytopenia, azotemia, and anuria, following an episode of bloody diarrhea.
Question:
What is the most likely etiologic agent?
A. Shigella dysenteriae
B. Enterohemorrhagic E. coli (EHEC)
C. Salmonella typhi
D. Campylobacter jejuni
Which of the following viral exanthems is associated with congenital infection that may result in cataracts, sensorineural deafness, and congenital heart disease?
A. Measles
B. Varicella
C. Rubella
D. Roseola infantum
Each of the following has been associated with Ascaris lumbricoides infection in humans, EXCEPT:
A. Löffler-like syndrome
B. Urticaria
C. Anemia
D. Intussusception
A 3-year-old child presents with:
* Low-grade fever
* Cough
* Leukocytosis: 90,000/mm3
* 90% neutrophils
Question:
Given this presentation, what is the most likely etiologic agent?
A. Ancylostoma duodenale
B. Enterobius vermicularis
C. Ascaris lumbricoides
D. Toxocara canis
Which of the following parasites does NOT infect via the percutaneous route?
A. Strongyloides stercoralis
B. Ancylostoma duodenale
C. Schistosoma spp.
D. Echinococcus granulosus
A 14-year-old adolescent presents with:
* Low-grade fever
* Generalized maculopapular rash (face → trunk → extremities)
* Posterior cervical and postauricular lymphadenopathy
* Mild conjunctivitis (red eyes)
* Joint pains (arthralgia)
Question:
What is the most likely diagnosis?
A. Measles
B. Rubella (German measles)
C. Roseola infantum
D. Scarlet fever
The Sabin-Feldman dye test is used in the diagnosis of which of the following infections?
A. Cytomegalovirus
B. Rubella
C. Toxoplasma gondii
D. Herpes simplex virus
What is the most common fungal infection in neonates?
A. Candida parapsilosis
B. Cryptococcus neoformans
C. Aspergillus fumigatus
D. Histoplasma capsulatum
A 3-year-old boy presents with:
* Fever for 3 days
* Red throat with tender, enlarged cervical lymph nodes
* Slight resistance to neck flexion
Question:
What is the next best step in management?
A. Perform lumbar puncture
B. Start empiric antibiotics
C. Obtain throat swab for culture
D. Give antipyretics and observe
What is the leading cause of bacterial meningitis in children between the ages of 6 months and 3 years (in unvaccinated populations)?
A. Neisseria meningitidis
B. Streptococcus pneumoniae
C. Haemophilus influenzae type b
D. Listeria monocytogenes
Which of the following parasites does NOT cause disease during its migration through parenchymal tissues?
A. Ascaris lumbricoides
B. Schistosoma spp.
C. Strongyloides stercoralis
D. Enterobius vermicularis
Which parasitic infection causes a type of dermatitis commonly referred to as “ground itch”?
A. Enterobius vermicularis
B. Ancylostoma duodenale
C. Trichuris trichiura
D. Taenia solium
Cysticercosis is caused by which of the following parasites?
A. Taenia saginata
B. Echinococcus granulosus
C. Diphyllobothrium latum
D. Taenia solium
A 2-year-old child presents with:
* High-grade fever (up to 40°C)
* Lethargy
* Vesicular rash
* New lesions continue to appear over the next 4 days, especially in the
afternoon
* Lesions at different stages of evolution (macules, papules, vesicles, crusts)
Question:
What is the most likely diagnosis?
A. Measles
B. Scarlet fever
C. Varicella (chickenpox)
D. Roseola infantum
A 2-year-old child is brought to the clinic due to intense perianal itching (pruritus ani), especially at night. The child is otherwise active and healthy.
Question:
What is the most likely cause of this symptom?
A. Giardia lamblia
B. Strongyloides stercoralis
C. Enterobius vermicularis
D. Ascaris lumbricoides
A 4-month-old infant presents with a 4-week history of:
* Gagging, gasping, paroxysmal cough
* Afebrile
CBC reveals:
* WBC: 42,000/mm’ with lymphocytic predominance
* 10% atypical (crescent-shaped) lymphocytes
* Hemoglobin: 12 g/dL
* Platelets: 650,000/mm3
Question:
What is the most likely etiologic agent?
A. Mycoplasma pneumoniae
B. Respiratory syncytial virus (RSV)
C. Bordetella pertussis
D. Cytomegalovirus
An asymptomatic newborn was exposed to smear-positive TB and has been receiving INH prophylaxis for 3 months.
Question:
What should be done next?
A. Continue INH
B. Stop INH
C. Start Rifampicin
D. Perform Mantoux test and re-evaluate
A patient presents with a 2-week history of:
* Intermittent low-grade fever that is gradually increasing
* Headache
* Malaise
* Dry cough
* Abdominal pain
There is no obvious localizing sign, and the fever is persistent.
Question:
What is the most likely diagnosis?
A. Typhoid fever
B. Dengue fever
C. Pulmonary tuberculosis
D. Infectious mononucleosis