Abstract
Porcine juvenile pustular psoriasiform dermatitis (PJPPD) is a disease of young pigs and characterized by nonpruritic round eruption of skin. The cause of this disease is yet undetermined but is presumed to be genetic predisposition. There may be few opportunities for veterinarian to detect this disease compared with actual situation in field because these lesions resolve spontaneously in two months. The authors detected spontaneous PJPPD case and performed clinical and pathological studies on three pigs from one farm. The specific skin lesions were observed in the forty-day old pigs of mixed breed, which were produced by the sows received semen from the same boar, restrictively. However, there was no skin lesion of pigs in suckling or fattening periods. Grossly, lesions were commonly found on the ventral abdominal part as a papule and were spreaded to the skin of whole body. With the spreading of lesions centrifugally, skin was showed as a umbilicated plaques or mosaic pattern with a few pustules or crusts. Microscopically, the most prominent lesion was the psoriasiform hyperplasia with acanthosis, down growth of rete ridges, exocytosis of eosinophils and neutrophils, ballooning degeneration of superficial epidermis, and koilocytic degeneration of keratinocytes. Additionally, there were moderate dermal edema and severe mixed cellular infiltration, especially eosinophils. No infectious agent which can cause the skin lesion, was detected or cultured, and no lesion caused by infectious agents was also observed, pathologically. With pathological results of this study, it is supposed that pathogenesis or severity of PJPPD may be related to the infiltration of eosinophil or hypersensitivity.
