ABD ABD Photodermatology and UV Effects

Question 1

Which idiopathic photodermatosis is the most common, affecting up to 10-20% of the population in temperate climates?

Accepted Answer

Polymorphous light eruption (PMLE)

Answer

Polymorphous light eruption (PMLE) is the most common idiopathic photodermatosis, presenting with pruritic papules, plaques, or vesicles on sun-exposed skin in spring/summer.

Question 2

UVA radiation (320-400nm) primarily penetrates to which level of the skin?

Accepted Answer

Dermis

Answer

UVA radiation penetrates deeply into the dermis, reaching dermal fibroblasts and blood vessels, and is the primary driver of photoaging and tanning through oxidative mechanisms.

Question 3

How does photoallergic contact dermatitis differ from phototoxic dermatitis?

Accepted Answer

Photoallergic reactions require prior sensitization and involve a Type IV immune response

Answer

Photoallergic reactions require prior sensitization, involve a Type IV delayed hypersensitivity immune response, and can spread beyond directly sun-exposed sites.

Question 4

Hydroa vacciniforme is associated with latent infection with which virus?

Accepted Answer

Epstein-Barr virus (EBV)

Answer

Hydroa vacciniforme and hydroa vacciniforme-like lymphoproliferative disorder are strongly associated with Epstein-Barr virus (EBV) infection.

Question 5

The Fitzpatrick skin phototype classification system categorizes human skin into how many phototypes?

Accepted Answer

6

Answer

The Fitzpatrick scale classifies skin into 6 phototypes (I-VI) based on constitutive pigmentation and the skin's response to UV exposure (burning versus tanning).

American Board of Dermatology (ABD) Practice Test

American Board of Dermatology (ABD) Practice Test

ABD ABD Photodermatology and UV Effects