Dermatology - AANP EXAM
PRACTICE with answers
1. A 45-year-old presents with an erythematous, scaly plaque
on the elbow and knee. Nail pitting is also noted. What is the
most likely diagnosis?
A. Atopic dermatitis
B. Psoriasis
C. Lichen planus
D. Tinea corporis
Answer: B. Psoriasis
Rationale: Psoriasis commonly presents as well-demarcated,
erythematous plaques with silvery scale on extensor surfaces
(elbows, knees) and is associated with nail pitting. Atopic
dermatitis is more flexural with itching. Lichen planus is purple,
polygonal, pruritic papules. Tinea corporis has an active border.
2. Which antifungal is preferred for tinea capitis in a 6-year-
old?
A. Topical clotrimazole
B. Terbinafine oral
C. Miconazole topical
D. Griseofulvin oral
,Answer: B. Terbinafine oral
Rationale: Tinea capitis requires systemic therapy. Terbinafine is
FDA-approved and effective for Trichophyton species. Griseofulvin
is also used but has more side effects and longer duration.
Topicals are ineffective for hair follicle infection.
3. A patient presents with a "bullseye" rash after a tick bite.
What is the next best step?
A. Doxycycline 100 mg BID x 14 days
B. Refer to infectious disease
C. Perform Western blot
D. Observe for 2 weeks
Answer: A. Doxycycline 100 mg BID x 14 days
Rationale: Erythema migrans (bullseye) is diagnostic of Lyme
disease. Treatment should be initiated immediately without
waiting for serology. Doxycycline is first-line for non-pregnant
adults.
4. What is the most common skin cancer type?
A. Melanoma
B. Squamous cell carcinoma
C. Basal cell carcinoma
D. Merkel cell carcinoma
,Answer: C. Basal cell carcinoma
Rationale: BCC accounts for ~80% of non-melanoma skin cancers.
It is locally invasive but rarely metastasizes. SCC is second most
common; melanoma is less common but more deadly.
5. Which describes an actinic keratosis?
A. Pearly papule with telangiectasias
B. Rough, erythematous scaly macule on sun-exposed skin
C. Firm, dome-shaped nodule with central keratotic plug
D. Irregular pigmented macule with asymmetry
Answer: B. Rough, erythematous scaly macule on sun-
exposed skin
Rationale: Actinic keratoses are premalignant lesions from sun
damage. They feel like sandpaper. Pearly papule with
telangiectasias = BCC; Keratoacanthoma (C) is a variant of SCC;
(D) suggests melanoma.
6. A patient has vesicular lesions in a dermatomal distribution
on the left thorax. What is the most likely diagnosis?
A. Herpes simplex
B. Contact dermatitis
C. Herpes zoster
D. Impetigo
, Answer: C. Herpes zoster
Rationale: Unilateral, dermatomal vesicles = shingles (varicella-
zoster reactivation). Herpes simplex is usually perioral or genital.
Contact dermatitis is not dermatomal.
7. Which medication is first-line for acute herpes zoster in
immunocompetent adults?
A. Acyclovir
B. Valacyclovir
C. Famciclovir
D. Topical lidocaine
Answer: B. Valacyclovir
Rationale: Valacyclovir has better bioavailability and less frequent
dosing (tid vs 5x/day for acyclovir). All are effective, but
valacyclovir is preferred for convenience and compliance.
8. A 22-year-old with acne has inflammatory papules and
pustules on the face and chest. What is first-line topical
therapy?
A. Benzoyl peroxide
B. Tretinoin cream
C. Clindamycin lotion
D. Benzoyl peroxide + topical antibiotic
PRACTICE with answers
1. A 45-year-old presents with an erythematous, scaly plaque
on the elbow and knee. Nail pitting is also noted. What is the
most likely diagnosis?
A. Atopic dermatitis
B. Psoriasis
C. Lichen planus
D. Tinea corporis
Answer: B. Psoriasis
Rationale: Psoriasis commonly presents as well-demarcated,
erythematous plaques with silvery scale on extensor surfaces
(elbows, knees) and is associated with nail pitting. Atopic
dermatitis is more flexural with itching. Lichen planus is purple,
polygonal, pruritic papules. Tinea corporis has an active border.
2. Which antifungal is preferred for tinea capitis in a 6-year-
old?
A. Topical clotrimazole
B. Terbinafine oral
C. Miconazole topical
D. Griseofulvin oral
,Answer: B. Terbinafine oral
Rationale: Tinea capitis requires systemic therapy. Terbinafine is
FDA-approved and effective for Trichophyton species. Griseofulvin
is also used but has more side effects and longer duration.
Topicals are ineffective for hair follicle infection.
3. A patient presents with a "bullseye" rash after a tick bite.
What is the next best step?
A. Doxycycline 100 mg BID x 14 days
B. Refer to infectious disease
C. Perform Western blot
D. Observe for 2 weeks
Answer: A. Doxycycline 100 mg BID x 14 days
Rationale: Erythema migrans (bullseye) is diagnostic of Lyme
disease. Treatment should be initiated immediately without
waiting for serology. Doxycycline is first-line for non-pregnant
adults.
4. What is the most common skin cancer type?
A. Melanoma
B. Squamous cell carcinoma
C. Basal cell carcinoma
D. Merkel cell carcinoma
,Answer: C. Basal cell carcinoma
Rationale: BCC accounts for ~80% of non-melanoma skin cancers.
It is locally invasive but rarely metastasizes. SCC is second most
common; melanoma is less common but more deadly.
5. Which describes an actinic keratosis?
A. Pearly papule with telangiectasias
B. Rough, erythematous scaly macule on sun-exposed skin
C. Firm, dome-shaped nodule with central keratotic plug
D. Irregular pigmented macule with asymmetry
Answer: B. Rough, erythematous scaly macule on sun-
exposed skin
Rationale: Actinic keratoses are premalignant lesions from sun
damage. They feel like sandpaper. Pearly papule with
telangiectasias = BCC; Keratoacanthoma (C) is a variant of SCC;
(D) suggests melanoma.
6. A patient has vesicular lesions in a dermatomal distribution
on the left thorax. What is the most likely diagnosis?
A. Herpes simplex
B. Contact dermatitis
C. Herpes zoster
D. Impetigo
, Answer: C. Herpes zoster
Rationale: Unilateral, dermatomal vesicles = shingles (varicella-
zoster reactivation). Herpes simplex is usually perioral or genital.
Contact dermatitis is not dermatomal.
7. Which medication is first-line for acute herpes zoster in
immunocompetent adults?
A. Acyclovir
B. Valacyclovir
C. Famciclovir
D. Topical lidocaine
Answer: B. Valacyclovir
Rationale: Valacyclovir has better bioavailability and less frequent
dosing (tid vs 5x/day for acyclovir). All are effective, but
valacyclovir is preferred for convenience and compliance.
8. A 22-year-old with acne has inflammatory papules and
pustules on the face and chest. What is first-line topical
therapy?
A. Benzoyl peroxide
B. Tretinoin cream
C. Clindamycin lotion
D. Benzoyl peroxide + topical antibiotic
