17 - 92 - POLYMORPHIC LIGHT ERUPTION

Question 1

most common photodermatosis, with a high prevalence, particularly among young women, in temperate climates

Answer 1

Polymorphic light eruption (PMLE)

Question 2

areas spared in Polymorphic light eruption (PMLE)

Answer 2

face and hands

• presumably because of continuous natural hardening resulting from daily sun exposure

Question 3

Question 4

most common form of Polymorphic light eruption (PMLE)

Answer 4

The papular form, characterized by large or small separate or confluent erythematous and edematous papules that may form clusters, is most common

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Diagnostic Criteria for Polymorphic Light Eruption

Answer 13

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Question 15

When is photoprovocation best perfomed

Answer 15

Photoprovocation is best performed before the beginning of the sunny summer season, preferentially in early spring, to avoid the false-negative results that may occur when the test is done too late in the season (ie, late spring or summer) because of tolerance induction through natural photohardening.

Question 16

principles of photoprovocation

Answer 16

• 2 symmetrically located test areas at predilection sites, preferably on previously involved skin, are exposed daily for 4 to 5 days to increasing suberythemal or near-erythemal doses of UVA or UVB radiation (or solar-simulated UV radiation).

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Question 22

suggested pathophysiology of PMLE

Answer 22

resistance to ultraviolet (UV)-induced immune suppression with subsequent delayed-type hypersensitivity reaction against UV-induced antigen(s)

Question 23

T or F. Sunburn is not mandatory for the development of a PMLE skin rash.

Answer 23

True

Question 24

Most common primary lesion of PMLE

Answer 24

Papule

Question 25

Most common UV radiation causing PMLE

Answer 25

UVA radiation (320 - 400 nm)

Question 26

True about PMLE except: a. PMLE is seen more frequently in temperate latitudes and rarely in equatorial latitudes b. PMLE usually has its onset within the first 6 decades of life and affects females approximately 4 times more often than males. c. PMLE patients with skin types I to IV, PMLE had the highest prevalence in individuals with skin type I. d. PMLE is the most common photo dermatosis

Answer 26

B Page 1611. Similar to many autoimmune disorders PMLE usually has its onset within the first 3 decades of life and affects females approximately 4 times more often than males.

Question 27

True of PMLE except: a. Once UV exposure ceases, all lesions of PMLE gradually resolve fully without scarring over several days, occasionally taking 7 to 10 days. b. PMLE can also occur after recreational sunbed use. c. Itching may be noted as the first sign of an impending PMLE eruption. d. UVB (290 to 320 nm) usually seems more causative than UVA (320 to 400nm) at initiating PMLE.

Answer 27

D UVA radiation (320 to 400 nm) usually seems more causative than UVB (290 to 320 nm) at initiating PMLE.

Question 28

Mechanism of photohardening except a. Melanization in the skin b. Thinning of the stratum corneum c. Restoration of immunologic susceptibility d. None of the above

Answer 28

B The mechanisms underlying the photohardening effect include melanization in the skin, thickening of the stratum corneum, and restoration of immunologic susceptibility, especially the impaired UVinduced Langerhans cells depletion, neutrophil infiltration, and neutrophil responsiveness to chemoattractants.

Question 29

True of PMLE except a. PMLE increases risk of skin cancer. b. Genetic factors seem to play a role in PMLE, as a polygenic model indicated PMLE inheritance. c. PMLE lesions may precede the development of lupus. d. Within several hours to days, but usually not less than 30 minutes, after the first exposure to an intense dose of sunlight, usually in spring or early summer, itchy skin lesions of variable morphology appear on sun-exposed skin.

Answer 29

A Together, this makes PMLE a potential skin cancer protective condition.

Question 30

Areas spared by PMLE includes: a. Face b. Hands c. Upper Chest d. Extensor aspect of arms e. Both A and B

Answer 30

E In contrast, the face and the hands of patients with PMLE are typically spared, presumably because of continuous natural hardening resulting from daily sun exposure.

Question 31

suggested pathogenesis of PMLE

Answer 31

resistance to ultraviolet (UV)-induced immune suppression (a physiologic phenomenon in healthy individuals) and a subsequent immune reaction to UV-modified elements in the skin are suggested

Question 32

specific variant of PMLE linked to the **African American** population of the northern states of the United States (Michigan) and **dark-skinned individuals in Asia **(eg, Singapore, Taiwan, and India)

Answer 32

pinpoint papular variant

Question 33

may be noted as the first sign of an impending PMLE eruption

Answer 33

itching

Question 34

areas of predilection of PMLE

Answer 34

sun-exposed areas that are normally covered during winter such as the** upper chest and the extensor aspects of the arms are most affected**

Question 35

variant of PMLE has been described in people with skin phototypes IV to VI, which is characterized by the development of very small papules on sun-exposed areas, including the face

Answer 35

pinpoint papular variant

Question 36

localized subtype of PMLE which tends to affect **boys in the spring** and is characterized by **pruritic papules and vesicles on their ear helices**

Answer 36

juvenile spring eruption

Question 37

to confirm PMLE, what test is performed?

Answer 37

photoprovocation

Question 38

What is the result when PMLE is tested for their UVB-induced or UVA-induced minimal erythema dose?

Answer 38

Normal ## Footnote * To confirm the diagnosis when the history and clinical features are not diagnostic, photoprovocation is performed in clinical practice to reproduce PMLE lesions, allowing also a subsequent skin biopsy.