1
I-Human Case Week 4 Skin Problem 25-Year-Old
Male Primary Care Dermatology Actual Exam
2026/2027 – Complete Exam-Style Questions with
Detailed Rationales | 100% Verified – Pass
Guaranteed – A+ Graded
[History Taking & Differential Diagnosis]
Q1: You are seeing Mark, a 25-year-old male, who presents with a chief complaint of "a rash that
started on my stomach and is spreading." To best characterize the onset and progression of his
skin condition, which is the most appropriate initial question to ask?
A. Have you been running a fever or feeling tired lately?
B. Did the rash start as a single spot, or did it appear all over your body at the same time?
C. Are you using any new laundry detergents or soaps on your clothes?
D. Does the rash itch or hurt to the touch?
Correct Answer: B
Rationale: The best answer is B because distinguishing between a single lesion that later spread
(suggesting a condition like Pityriasis Rosea with a herald patch) versus a simultaneous onset
(suggesting a drug eruption or viral exanthem) is critical for narrowing your differential
diagnosis right from the start.
Q2: Mark reports that the rash began about two weeks ago as a single, "scaly pink spot" on his
abdomen, but now he notices multiple smaller spots on his chest and back. Based on this history
alone, which differential diagnosis is most consistent with this "herald patch" presentation?
A. Tinea corporis (ringworm)
B. Pityriasis rosea
C. Psoriasis
D. Contact dermatitis
Correct Answer: B
,2
Rationale: This choice is correct because Pityriasis rosea classically begins with a solitary
"herald patch" on the trunk, followed 1 to 2 weeks later by a generalized, smaller, oval rash along
skin tension lines.
Q3: When further questioning Mark about associated symptoms, he denies fever, chills, or joint
pain but admits the rash is "pretty itchy." Which of the following questions is most critical to rule
out a life-threatening cause of his rash?
A. Have you had any recent unprotected sexual encounters?
B. Do you have a family history of eczema or psoriasis?
C. Are you taking any new medications, including antibiotics or NSAIDs?
D. Have you recently been camping or hiking in wooded areas?
Correct Answer: C
Rationale: The best answer is C because ruling out a drug eruption (like Stevens-Johnson
Syndrome or DRESS) is vital; even though Mark denies systemic symptoms now, certain
medication reactions can start subtly and progress rapidly, making this a safety priority.
Q4: Mark mentions he started a new workout supplement and protein powder three weeks ago,
but he can't remember the names. In the context of his rash, why is identifying specific
supplements or over-the-counter products important?
A. Supplements often contain hidden allergens like soy or gluten that cause immediate hives.
B. Protein powders are known to cause fungal infections like tinea corporis.
C. Many supplements contain herbal ingredients that can cause liver toxicity, mimicking skin
jaundice.
D. Some products contain additives or "fillers" that can trigger fixed drug eruptions or
hypersensitivity reactions.
Correct Answer: D
Rationale: This choice is correct because over-the-counter supplements often contain unlisted
dyes, preservatives, or herbal compounds that are common culprits for fixed drug eruptions or
morbilliform drug rashes in young adults.
, 3
Q5: You ask Mark about the distribution of the rash. He says, "It's mostly on my chest, stomach,
and back, and it seems to be following the lines of my ribs." Which descriptor best fits this
pattern?
A. Dermatomal
B. Christmas tree pattern
C. Flexural distribution
D. Photodistributed
Correct Answer: B
Rationale: The best answer is B because the "Christmas tree pattern" describes the distribution of
oval lesions along the lines of skin tension (Langer's lines) on the trunk, which is pathognomonic
for Pityriasis rosea.
Q6: Considering Mark's age and presentation, which item in his social history would be most
relevant to explore regarding the risk of secondary syphilis, a condition that can mimic Pityriasis
rosea?
A. Occupation as a software developer
B. History of playing contact sports in college
C. Recent travel to the Midwest
D. Number of recent sexual partners and condom use
Correct Answer: D
Rationale: This choice is correct because secondary syphilis presents with a widespread rash,
often involving the palms and soles, and is a sexually transmitted infection; assessing sexual risk
is the only way to effectively determine if this differential needs to be pursued with serology.
Q7: Mark denies any lesions on his palms or soles. How does this specific negative finding
influence your differential diagnosis?
A. It rules out Psoriasis completely.
B. It makes secondary syphilis much less likely.
C. It confirms the diagnosis of Atopic dermatitis.
D. It suggests the rash is not fungal in origin.
I-Human Case Week 4 Skin Problem 25-Year-Old
Male Primary Care Dermatology Actual Exam
2026/2027 – Complete Exam-Style Questions with
Detailed Rationales | 100% Verified – Pass
Guaranteed – A+ Graded
[History Taking & Differential Diagnosis]
Q1: You are seeing Mark, a 25-year-old male, who presents with a chief complaint of "a rash that
started on my stomach and is spreading." To best characterize the onset and progression of his
skin condition, which is the most appropriate initial question to ask?
A. Have you been running a fever or feeling tired lately?
B. Did the rash start as a single spot, or did it appear all over your body at the same time?
C. Are you using any new laundry detergents or soaps on your clothes?
D. Does the rash itch or hurt to the touch?
Correct Answer: B
Rationale: The best answer is B because distinguishing between a single lesion that later spread
(suggesting a condition like Pityriasis Rosea with a herald patch) versus a simultaneous onset
(suggesting a drug eruption or viral exanthem) is critical for narrowing your differential
diagnosis right from the start.
Q2: Mark reports that the rash began about two weeks ago as a single, "scaly pink spot" on his
abdomen, but now he notices multiple smaller spots on his chest and back. Based on this history
alone, which differential diagnosis is most consistent with this "herald patch" presentation?
A. Tinea corporis (ringworm)
B. Pityriasis rosea
C. Psoriasis
D. Contact dermatitis
Correct Answer: B
,2
Rationale: This choice is correct because Pityriasis rosea classically begins with a solitary
"herald patch" on the trunk, followed 1 to 2 weeks later by a generalized, smaller, oval rash along
skin tension lines.
Q3: When further questioning Mark about associated symptoms, he denies fever, chills, or joint
pain but admits the rash is "pretty itchy." Which of the following questions is most critical to rule
out a life-threatening cause of his rash?
A. Have you had any recent unprotected sexual encounters?
B. Do you have a family history of eczema or psoriasis?
C. Are you taking any new medications, including antibiotics or NSAIDs?
D. Have you recently been camping or hiking in wooded areas?
Correct Answer: C
Rationale: The best answer is C because ruling out a drug eruption (like Stevens-Johnson
Syndrome or DRESS) is vital; even though Mark denies systemic symptoms now, certain
medication reactions can start subtly and progress rapidly, making this a safety priority.
Q4: Mark mentions he started a new workout supplement and protein powder three weeks ago,
but he can't remember the names. In the context of his rash, why is identifying specific
supplements or over-the-counter products important?
A. Supplements often contain hidden allergens like soy or gluten that cause immediate hives.
B. Protein powders are known to cause fungal infections like tinea corporis.
C. Many supplements contain herbal ingredients that can cause liver toxicity, mimicking skin
jaundice.
D. Some products contain additives or "fillers" that can trigger fixed drug eruptions or
hypersensitivity reactions.
Correct Answer: D
Rationale: This choice is correct because over-the-counter supplements often contain unlisted
dyes, preservatives, or herbal compounds that are common culprits for fixed drug eruptions or
morbilliform drug rashes in young adults.
, 3
Q5: You ask Mark about the distribution of the rash. He says, "It's mostly on my chest, stomach,
and back, and it seems to be following the lines of my ribs." Which descriptor best fits this
pattern?
A. Dermatomal
B. Christmas tree pattern
C. Flexural distribution
D. Photodistributed
Correct Answer: B
Rationale: The best answer is B because the "Christmas tree pattern" describes the distribution of
oval lesions along the lines of skin tension (Langer's lines) on the trunk, which is pathognomonic
for Pityriasis rosea.
Q6: Considering Mark's age and presentation, which item in his social history would be most
relevant to explore regarding the risk of secondary syphilis, a condition that can mimic Pityriasis
rosea?
A. Occupation as a software developer
B. History of playing contact sports in college
C. Recent travel to the Midwest
D. Number of recent sexual partners and condom use
Correct Answer: D
Rationale: This choice is correct because secondary syphilis presents with a widespread rash,
often involving the palms and soles, and is a sexually transmitted infection; assessing sexual risk
is the only way to effectively determine if this differential needs to be pursued with serology.
Q7: Mark denies any lesions on his palms or soles. How does this specific negative finding
influence your differential diagnosis?
A. It rules out Psoriasis completely.
B. It makes secondary syphilis much less likely.
C. It confirms the diagnosis of Atopic dermatitis.
D. It suggests the rash is not fungal in origin.
