Home
This site is intended for healthcare professionals
USMLE Step 1 Community
USMLE Step 1 Community
189 followers
Posted by Nikki M  |  10 Dec 2024
10 Dec 2024

scarlet fever

A 58-year-old man presents with history of recurrent rashes that became severe in the last week. The rashes were erythematous with a fine, sandpaper-like texture. He also reports having a fever and symptoms of a sore throat two weeks prior to the rash. Examination reveals a 'strawberry tongue'. Based on the history and physical examination, what mechanism is the most likely cause of this patient's symptoms?

correct answer: type 4 hypersensitivity

I picked the answer "direct toxins from bacterial exotoxins"

why is this type 4 hypersensitivity? please explain

Question:
A 58-year-old man presents with history of recurrent rashes that became severe in the last week. The rashes were erythematous with a fine, sandpaper-like texture. He also reports having a fever and symptoms of a sore throat two weeks prior to the rash. Examination reveals a 'strawberry tongue'. Based on the history and physical examination, what mechanism is the most likely cause of this patient's symptoms?
Options:
A)Type I hypersensitivity reaction
B)Type II hypersensitivity reaction
C)Type III hypersensitivity reaction
D)Type IV hypersensitivity reaction
E)Direct toxicity from bacterial exotoxins
→ View this question

scarlet fever

A 58-year-old man presents with history of recurrent rashes that became severe in the last week. The rashes were erythematous with a fine, sandpaper-like texture. He also reports having a fever and symptoms of a sore throat two weeks prior to the rash. Examination reveals a 'strawberry tongue'. Based on the history and physical examination, what mechanism is the most likely cause of this patient's symptoms?

correct answer: type 4 hypersensitivity

I picked the answer "direct toxins from bacterial exotoxins"

why is this type 4 hypersensitivity? please explain

Question:
A 58-year-old man presents with history of recurrent rashes that became severe in the last week. The rashes were erythematous with a fine, sandpaper-like texture. He also reports having a fever and symptoms of a sore throat two weeks prior to the rash. Examination reveals a 'strawberry tongue'. Based on the history and physical examination, what mechanism is the most likely cause of this patient's symptoms?
Options:
A)Type I hypersensitivity reaction
B)Type II hypersensitivity reaction
C)Type III hypersensitivity reaction
D)Type IV hypersensitivity reaction
E)Direct toxicity from bacterial exotoxins
→ View this question
Rashella DAmico15 Dec 2024(Edited)
15 Dec 2024(Edited)

You're right! This is a bad answer to the question. The immune-mediated reaction involved in scarlet fever, triggered by streptococcal exotoxins, is primarily considered a Type II hypersensitivity reaction. However, the rash and systemic symptoms in scarlet fever are more closely related to toxin-induced effects rather than a classic antibody-mediated attack on host tissues.

You're right! This is a bad answer to the question. The immune-mediated reaction involved in scarlet fever, triggered by streptococcal exotoxins, is primarily considered a Type II hypersensitivity reaction. However, the rash and systemic symptoms in scarlet fever are more closely related to toxin-induced effects rather than a classic antibody-mediated attack on host tissues.