AANP Dermatology 2 — Questions and Answers
Question 1: Tzanck smear revealing multinucleated giant cells is consistent with infection caused by which organism?
- Staphylococcus aureus
- Candida albicans
- Herpes simplex virus (Correct answer)
- Human papillomavirus
Correct answer: Herpes simplex virus
Multinucleated giant cells (Tzanck cells) on smear are pathognomonic for herpesvirus infections, including HSV-1, HSV-2, and varicella-zoster virus.
Question 2: Which topical medication is the treatment of choice for tinea pedis (athlete's foot)?
- Topical corticosteroids
- Topical clotrimazole or terbinafine (Correct answer)
- Topical mupirocin
- Topical acyclovir
Correct answer: Topical clotrimazole or terbinafine
Tinea pedis is a dermatophyte fungal infection treated with topical antifungals such as clotrimazole (azole) or terbinafine (allylamine) applied for 2–4 weeks.
Question 3: A patient on a biologic therapy for psoriasis should be screened for which infection before initiating treatment?
- Streptococcal infection
- Latent tuberculosis (Correct answer)
- Helicobacter pylori
- Hepatitis A
Correct answer: Latent tuberculosis
TNF-alpha inhibitors and other biologics used for psoriasis increase the risk of reactivating latent TB; a tuberculin skin test or IGRA must be performed before initiation.
Question 4: What is the most common cause of bacterial impetigo in children in the United States?
- Group A Streptococcus alone
- Staphylococcus aureus (including MRSA) (Correct answer)
- Pseudomonas aeruginosa
- Haemophilus influenzae
Correct answer: Staphylococcus aureus (including MRSA)
Staphylococcus aureus is the predominant cause of impetigo in the US, with MRSA increasingly common; it presents as honey-crusted lesions on the face and extremities.
Question 5: A patient reports a skin lesion that began as a papule and developed a central depression with umbilication. What is the most likely diagnosis?
- Basal cell carcinoma
- Molluscum contagiosum (Correct answer)
- Sebaceous cyst
- Keratoacanthoma
Correct answer: Molluscum contagiosum
Molluscum contagiosum, caused by a poxvirus, produces dome-shaped papules with a characteristic central umbilication (depression) that distinguish it from other skin lesions.
Question 6: Which skin finding is most associated with systemic lupus erythematosus (SLE)?
- Butterfly (malar) rash across the nose and cheeks (Correct answer)
- Erythema chronicum migrans
- Port-wine stain
- Acanthosis nigricans
Correct answer: Butterfly (malar) rash across the nose and cheeks
The malar (butterfly) rash of SLE spares the nasolabial folds and is triggered or worsened by UV light exposure, representing a classic diagnostic criterion.
AANP Dermatology 2
Tzanck smear revealing multinucleated giant cells is consistent with infection caused by which organism?