ITE Allergy and Immunology

Question 1

A 28-year-old woman develops urticaria, angioedema, bronchospasm, and hypotension within 15 minutes of receiving amoxicillin. Which of the following is the MOST critical immediate intervention?

Accepted Answer

Epinephrine 0.3–0.5 mg IM into the anterolateral thigh

Answer

Diphenhydramine 50 mg IV

Answer

Methylprednisolone 125 mg IV

Answer

Albuterol inhaler for bronchospasm

Question 2

A 35-year-old man develops angioedema of the lip and tongue 2 weeks after starting lisinopril for hypertension. He has no urticaria and no prior allergic history. Which mechanism best explains this reaction?

Accepted Answer

Bradykinin accumulation due to ACE inhibition

Answer

IgE-mediated mast cell degranulation

Answer

Complement-mediated C1 esterase inhibitor deficiency

Answer

Direct histamine release from lisinopril

Question 3

A 6-month-old boy has had recurrent pneumonia caused by Pneumocystis jirovecii, oral candidiasis, and failure to thrive since birth. On examination, no lymph nodes are palpable. CBC shows lymphopenia. Which immunodeficiency is most likely?

Accepted Answer

Severe combined immunodeficiency (SCID)

Answer

X-linked agammaglobulinemia (XLA)

Answer

Common variable immunodeficiency (CVID)

Answer

DiGeorge syndrome

Question 4

A 25-year-old woman develops a diffuse maculopapular rash 10 days after starting ampicillin for mononucleosis. She denies prior penicillin allergy. What is the correct interpretation of this reaction?

Accepted Answer

This is a non-allergic ampicillin rash associated with EBV infection, not a true penicillin allergy

Answer

This confirms true IgE-mediated penicillin allergy requiring permanent avoidance

Answer

She has delayed-type hypersensitivity (Type IV) to penicillin class antibiotics

Answer

She should receive immediate allergy testing to confirm cross-reactivity

Question 5

A 32-year-old woman has recurrent episodes of angioedema without urticaria, triggered by stress and minor trauma, with no identifiable allergen. Her C4 level is consistently low. C1 esterase inhibitor (C1-INH) level and function are markedly reduced. Family history reveals her father had similar episodes. What is the most likely diagnosis?

Accepted Answer

Hereditary angioedema (HAE) type I

Answer

ACE inhibitor-induced angioedema

Answer

Acquired angioedema from C1-INH deficiency

Answer

Idiopathic histaminergic angioedema

Question 6

A 45-year-old man with recurrent sinopulmonary infections since age 25 is found to have serum IgG of 280 mg/dL (normal 700–1600), IgA of 15 mg/dL, and IgM of 40 mg/dL. He has normal T cell counts but markedly reduced B cell numbers. What is the most appropriate long-term management?

Accepted Answer

Intravenous immunoglobulin (IVIG) replacement therapy

Answer

Prophylactic trimethoprim-sulfamethoxazole

Answer

Bone marrow transplantation

Answer

Subcutaneous interferon-gamma injections