Mast Cells Gone Wild
Antibodies Gone Rogue
Complex Problems with Complexes
T Minus 72 Hours
Friendly Fire
Test Me, Maybe
Fix It in the Clinic
It’s Not Always Allergies!
100
Which antibody triggers allergic rhinitis and anaphylaxis?
IgE
100
Which antibody types are typically involved in hemolytic transfusion reactions?
IgG & IgM
100
Post-strep glomerulonephritis follows what infection?
Strep throat (pharyngitis)
100
What skin condition is caused by poison ivy exposure?
Allergic contact dermatitis
100
What autoimmune disease causes ptosis and muscle weakness?
Myasthenia gravis
100
What test screens for lupus and other autoimmune conditions?
Antinuclear antibodies
100
What is the first-line treatment for mild to moderate allergic rhinitis?
Intranasal corticosteroids
100
A patient reports nasal congestion and sneezing every spring. However, they deny itching or watery eyes. What’s a likely non-allergic cause?
Vasomotor rhinitis
200
Which cytokine promotes IgE class switching in atopic patients?
IL-4
200
What receptor is targeted by autoantibodies in myasthenia gravis?
Acetylcholine receptor
200
What causes the rash in serum sickness?
Immune complex deposition in tissues
200
A nurse has a 14 mm induration 72 hours after a TB skin test. What type of immune response is this?
Type IV – T-cell mediated
of ≥5 mm for high-risk groups (e.g., HIV-infected individuals, recent contacts of TB cases),
≥10 mm for moderate-risk groups (e.g., recent arrivals from high-prevalence countries, healthcare workers),
≥15 mm for individuals with no known risk factors.
200
Hashimoto’s thyroiditis is classified as what hypersensitivity type?
Type 2
200
What does a positive direct Coombs test detect?
Autoantibodies on RBCs
200
What topical cream is used for mild contact dermatitis?
Low-potency corticosteroids
200
A 42-year-old woman presents with flushing, diarrhea, and wheezing that occur intermittently and are unrelated to food or seasonal changes. Physical exam is normal today. Which condition should be considered?
Bonus: what lab test may help confirm the diagnosis?
Carcinoid syndrome
24-hour urinary 5-HIAA
300
A patient presents with raised, itchy welts on the skin after a bee sting. What is this rash called and what hypersensitivity type?
Urticaria, Type I
300
What causes hemolytic disease of the newborn?
Maternal anti-Rh IgG antibodies
300
A 6-year-old has purpura on legs, abdominal pain, and joint swelling after a URI. Diagnosis?
IgA Vasculitis (Henoch-Schönlein Purpura) (Type III)
300
How long after exposure does a Type IV rash usually appear?
48–72 hours
300
What disease involves antibodies against desmoglein?
Pemphigus vulgaris
300
A 45-year-old patient presents with a pruritic rash on his wrist where his fitness tracker rests. The rash is erythematous with occasional vesicles and appears to worsen several days after wearing the device.
What is the most likely diagnosis, and what is the next best step in evaluation?
Allergic contact dermatitis; patch testing
300
Why is RhoGAM given to Rh-negative pregnant women?
To prevent maternal sensitization to fetal Rh+ blood
300
Which of the following is most likely to mimic anaphylaxis but presents with normal tryptase levels?
A. Hereditary angioedema
B. Peanut allergy
C. Latex allergy
D. Serum sickness
A. Hereditary angioedema
400
Why is measuring tryptase helpful in suspected anaphylaxis cases?
To confirm mast cell activation
400
A patient develops jaundice and hemoglobinuria after a mismatched blood transfusion. What hypersensitivity type is this?
Type II – cytotoxic
400
Where do immune complexes deposit in lupus nephritis?
Glomerular basement membrane
400
A 34-year-old nurse presents with pruritic, erythematous vesicles on her hands 48 hours after using a new brand of latex gloves. She denies systemic symptoms and reports similar reactions to nickel jewelry.
Which immune cells are primarily responsible for her symptoms?
Bonus points: what test could confirm the diagnosis?
Memory CD4+ T-cells
Patch testing
400
What disease features antibody stimulation of the TSH receptor?
Graves’ disease
400
A child has hematuria after strep throat. UA shows RBC casts. Most likely dx?
Post-strep glomerulonephritis
400
What monoclonal antibody is used for chronic idiopathic urticaria?
Omalizumab
Monoclonal anti-immunoglobulin E (IgE) antibody that works by selectively binding to the C-epsilon-3 locus of IgE, thereby lowering circulating free IgE levels and preventing IgE from interacting with inflammatory cells like mast cells and basophils, which breaks the allergic cascade and limits mediator release.
400
A 27-year-old woman presents with periorbital swelling, abdominal pain, and no urticaria. She had similar episodes in childhood. What test can confirm the diagnosis?
C4 level (low in hereditary angioedema)
500
A 24-year-old develops wheezing, hypotension, and vomiting after eating peanuts. What type of hypersensitivity is this? What is dosage to treat?
Type 1
0.01 mg per kg of body weight; max dose 0.5 mg q5-15 mins if pt doesnt respond
autoinjectors = 0.5 mg adult, 0.15 mg peds
500
What pattern is seen on biopsy in Goodpasture’s syndrome affecting kidneys?
Linear IgG deposition along the basement membrane
500
What complement levels are typically low in active lupus?
C3 and C4
500
What chemical in poison ivy causes the rash?
Urushiol
500
A 30-year-old woman presents with fatigue, joint stiffness, and a facial rash that worsens with sun exposure. Labs reveal anemia, thrombocytopenia, proteinuria, and a positive ANA. Anti-dsDNA and anti-Smith antibodies are also detected.
What is the most likely diagnosis, and which antibody finding is most specific for this condition?
Systemic lupus erythematosus (SLE); anti-Smith antibody
500
What is the precipitation of immune complexes in small vessels under the skin when antigen is injected in an animal with large amounts of circulating antibody?
Arthus reaction
500
A 29-year-old woman with known systemic lupus erythematosus presents to your outpatient clinic with new-onset lower extremity edema and fatigue. Labs show proteinuria and elevated creatinine. Urinalysis reveals RBC casts.
You refer her to nephrology. While awaiting evaluation, what medication should be initiated to reduce proteinuria and preserve renal function?
An ACE inhibitor or ARB
500
A patient presents with a rash that worsened after topical corticosteroid use for “eczema.” What’s the correct diagnosis?
Perioral dermatitis (not allergic contact dermatitis)
tx avoid irritant + topical abx