polymorphous light eruption

Question 1

isatermthatdescribesagroupo heterogeneous,idiopathic,acquired,andacuterecurrent eruptions characterized by delayed abnormal reactions to UVR.
■ Mani ested by varied lesions, including erythematous macules, papules, plaques, and vesicles. How- ever, in each patient, the eruption is consistently monomorphous.
■ By ar, the most requent morphologic types are the papular and papulovesicular eruptions

Answer 1

PMLE

Question 2

there is a heredi- tarytypeo PMLEthatiscalled

Answer 2

actinic prurigo

Question 3

onset

gender

Answer 3

Most common photodermatosis. Prevalence rom10%to21%.Average
ageo onsetis23yearsanditismuchmore commonin emales.Allraces,butmostcom- mon in SP I, II, and III. In American Indians (North and South America

Question 4

pathogenesis

Answer 4

Possibly a delayed-type hypersensitivity reac- tion to an (auto-) antigen induced by UVR. T e action spectrum is UVA and less commonly UVB or UVA and UVB. Since UVA is trans- mitted through window glass, PMLE can be precipitated while riding in a car.

Question 5

lesion

whatseason

Answer 5

ONSETANDDURATIONOFLESIONS PMLEappears in spring or early summer. It occurs within hourso exposureandonceestablished,it persists or7to10days.Symptomsaremassive pruritus. Scratching is pain ul.
SKIN LESIONS T e papular (Fig. 10-9) and papu- lovesiculartypesarethemost requent.Far
less common are plaques or urticarial plaques (Fig. 10-10). T e lesions are pink to red. In the individual patient, lesions are quite monomor- phous, i.e., either papular or papulovesicular orurticarialplaques.Recurrences ollowthe original pattern.
DISTRIBUTION T e eruption o en spares habitually exposed areas ( ace and neck) and appearsmost requentlyonthe orearms, upperarms,Vareao theneck,andchest
(Fig. 10-9). However, lesions may occur on the
ace(Fig.10-10),i therehasnotbeenprevious exposure to the sun.

Question 6

dermatopath

IF

Answer 6

Edema o the epider- mis,spongiosis,vesicle ormation,andmild

lique action degeneration o the basal layer withdenselymphocyticin ltrateinthedermis. IMMUNOFLUORESCENCE Negative ANA.

Question 7

mgt

Answer 7

PREVENTION Sunblocks are not always ef ective but should be tried rst in every patient.
Systemic β-carotene, 60 mg three times a day or 2 weeks, be ore going in the sun. Oral prednisone 20 mg/day given 2 days be ore and 2 days during exposure is a good prophylaxis. Also, intramuscular triamcinolone acetonide, 40 mg, will suppress an eruption when admin- istereda ewdaysbeoreatriptoasunny region.
PUVA (Photochemotherapy) and narrow- band UVB (311 nm) are very ef ective when given in early spring by inducing “tolerance”
or the summer. reatments have to be given be ore the sunny season, be repeated each spring, but are usually not necessary or more than 3 or 4 years.