Q-4. Once a keratinocyte leaves the basal cell layer, the normal transit time to stratum corneum is at least:
a) 7 days
b) 14 days
c) 21 days
d) 28 days
Answer: 14 days
Explanation:
Once a basal cell leaves the basal layer in humans, normal transit time to stratum corneum is at least 14 days. Transit time through the stratum corneum to desquamation requires 14 more days.
Q-5. Dermatitis herpetiformis is associated with:
B. HLA-B27
C. HLA-DR4
D. HLA-DP1
E. HLA-DR3
Answer: HLA-DR3
Explanation:
HLA DR3 and DQ2 are associated with dermatitis herpetiformis. HLA B27 is associated with psoriasis with spondylarthropathy.
Q-6. Which of the following is a sign of EARLY postnatal congenital syphilis?
a) Clutton’s joints
b) Hutchinson’s teeth
c) Saber shins
d) Wimberger’s sign
Answer: Wimberger’s sign
Explanation:
Wimberger’s sign is a sign of early postnatal congenital syphilis (occurs < 2 years old). All other choices are signs of late postnatal congenital syphilis. Wimberger’s sign is a radiographic sign showing a saw-tooth appearance of the proximal tibia. Important point:
It must not be confused with Wimberger ring sign seen in scurvy.
Q-7. The most common laboratory abnormality in patients treated with isotretinoin is:
a) Decreased white blood cell count
b) Increased cholesterol
c) Elevated liver enzymes
d) Hyper-triglyceridemia
Answer: Hyper-triglyceridemia
Explanation:
The most common laboratory abnormality seen in patients taking isotretinoin is increased triglycerides, followed by elevation of cholesterol, ALT and AST.
Q-8. What is the best muscle to biopsy in dermatomyositis?
a) Triceps
b) Biceps
c) Quadriceps
d) Deltoid
Answer: Triceps
Explanation:
The triceps muscle is involved early in the disease; therefore, it has the highest yield in a muscle biopsy looking for the changes seen in dermatomyositis.
Q-9. A 2 day-old full term neonate develops blotchy erythematous macules with small central pustules over the upper trunk and extremities. A gram stain reveals predominantly eosinophils. What is the most likely diagnosis?
a) Erythema toxicum neonatorum
b) Incontinentia pigmenti
c) Urticaria pigmentosa
d) Transient neonatal pustular melanosis
Answer: Erythema toxicum neonatorum
Explanation:
Erythema toxicum neonatorum is a very common, benign, self-limited eruption in healthy newborns. Erythema toxicum usually develops on the second or third day of life and resolves by day 10.
Important point:
A gram stain reveals sterile pustules containing eosinophils.
Q-10. A teenager comes into your office requesting laser hair removal of her significant facial hair. Before you agree to treat her, you order which of the following laboratory analyses?
a) FSH and LH
b) Ferritin and TIBC
c) Testosterone and DHEA-S
d) T3, T4 and TSH
Answer: Testosterone and DHEA-S
Explanation:
Hirsutism is under the influence of androgen stimulation. Testosterone and DHEA-S can be used to detect excessive adrenal or ovarian androgen production.
Q-11. Which of the following topical agents has effect of reducing sebum production?
a) Topical Nicotinamide
b) Topical erythromycin
c) Topical benzol peroxide
d) Topical azelaic acid
Answer: Topical Nicotinamide
Explanation:
A Nicotinamide reduces facial sebum production. Sebum is responsible for facial shine and contributes to non-inflamed comedones and inflammatory acne lesions.