Serial light microscopy of experimental phytophotodermatitis in animal model.
BACKGROUND
Phytophotodermatitis (PPD) is a common phototoxic eruption, but very little information is available about its histological aspects, as the diagnosis is clinically established.


METHODS
The epilated right half of the back of four albino rats was sprayed with peel juice of Tahiti lemon, one quadrant was exposed to sunlight for 5 min and the other for 8 min. The left back served as control. Biopsies were taken after 1, 2, 3, 4, 5, 6, 24, 48 and 72 h in both sides.


RESULTS
The first six time intervals showed a normal epidermis in both sides. After 24 h, the area with peel lemon juice showed keratinocyte necrosis, cytoplasmic vacuolization and spongiosis in all rats, independent of the exposure time. The control side showed isolated keratinocyte necrosis with only 8 min of exposure. After 48 h, erythema is evident and strong vacuolization was observed, which progresses to sub- or intraepidermal blisters. After 72 h, the erythema persisted and histological findings were less intense.


CONCLUSIONS
PPD can be successfully reproduced in rat skin. After 24 h spongiosis, vacuolization and keratinocyte necrosis are observed, clinically there are no changes. After 48 h, erythema appears with intra- and subepidermal blistering.
Jorge
Valeria M
VM
Department of Pathology, Catholic University of Pelotas, Pelotas, RS, Brazil.
de Almeida
Hiram L
HL
Amado
Milton
M
D000818:Animals; D001768:Blister / Q000139:chemically induced / Q000473:pathology; D002957:Citrus / Q000009:adverse effects*; D004195:Disease Models, Animal; D004890:Erythema / Q000139:chemically induced / Q000473:pathology; D005638:Fruit / Q000009:adverse effects*; D006801:Humans; D015603:Keratinocytes / Q000473:pathology; D008027:Light / Q000009:adverse effects*; D009336:Necrosis / Q000139:chemically induced / Q000473:pathology; D010787:Photosensitivity Disorders / Q000139:chemically induced / Q000473:pathology*; D051381:Rats; D013997:Time Factors