CHARACTERISTICS OF SPONTANEOUS ERYTHEMA APPEARED IN HAIRLESS RATS

The hairless rat (WBN/Kob-Ht), a dominant mutant rat derived from the Wistar strain, rarely develops spontaneous erythema of a progressive n ature on ifs skin. Erythema was first observed at 8 weeks of age and t he incidence at 20 weeks of age was about 4% in both males and females . Histopathologically, erythema was characterised by dermatitis induce d by an immunological reaction. Areas of erythema in the skin were dec reased by treatment with dexamethasone (1 mg/kg) or ciclosporin (25 or 50 mg/kg). These results suggested that erythema on the hairless rat could be used as an animal model of spontaneous dermatitis.