ABD ABD Hair and Nail Disorders 1 — Questions and Answers
Question 1: What is the most common cause of diffuse hair loss in adult women in the US?
- Alopecia areata
- Female pattern hair loss (androgenetic alopecia) (Correct answer)
- Telogen effluvium
- Traction alopecia
Correct answer: Female pattern hair loss (androgenetic alopecia)
Female pattern hair loss (androgenetic alopecia) is the most common cause of hair loss in adult women, affecting up to 40% by age 50.
Question 2: Which dermoscopic finding is pathognomonic for alopecia areata?
- Black dots (cadaverized hairs) (Correct answer)
- Perifollicular scaling
- Fibrotic white dots
- Comma hairs only
Correct answer: Black dots (cadaverized hairs)
Black dots (cadaverized hairs), exclamation mark hairs, and yellow dots are all characteristic dermoscopic features of alopecia areata.
Question 3: Onychomycosis is most commonly caused by which organism in the United States?
- Candida albicans
- Trichophyton rubrum (Correct answer)
- Trichophyton mentagrophytes
- Epidermophyton floccosum
Correct answer: Trichophyton rubrum
Trichophyton rubrum accounts for approximately 70-80% of onychomycosis cases in the US and is the predominant causative dermatophyte.
Question 4: Nail pitting is a manifestation of psoriasis affecting which part of the nail unit?
- Nail bed
- Nail matrix (Correct answer)
- Hyponychium
- Lateral nail fold
Correct answer: Nail matrix
Nail pitting results from focal parakeratosis in the proximal nail matrix that sloughs off, leaving small depressions on the nail surface.
Question 5: Yellow nail syndrome is classically defined by which triad?
- Yellow nails, lymphedema, and pleural effusions (Correct answer)
- Yellow nails, onycholysis, and paronychia
- Yellow nails, clubbing, and cyanosis
- Yellow nails, pachyonychia, and hyperhidrosis
Correct answer: Yellow nails, lymphedema, and pleural effusions
Yellow nail syndrome is characterized by slow-growing yellow nails with onycholysis, lymphedema, and pleural effusions or other respiratory manifestations.
Question 6: Acral lentiginous melanoma disproportionately affects which population and frequently presents as subungual melanoma?
- Fair-skinned individuals of Northern European descent
- Non-Hispanic Black and Asian patients (Correct answer)
- Hispanic patients exclusively
- Patients with Fitzpatrick type III skin only
Correct answer: Non-Hispanic Black and Asian patients
Acral lentiginous melanoma is the most common melanoma subtype in non-Hispanic Black and Asian populations, frequently arising in the nail unit as subungual melanoma.
ABD ABD Hair and Nail Disorders 1
What is the most common cause of diffuse hair loss in adult women in the US?