SPONTANEOUS SKIN-LESIONS IN BEIGE RATS (CHEDIAK-HIGASHI-SYNDROME OF RATS)

Beige rats, a model animal of Chediak-Higashi syndrome (CHS), frequent ly developed the skin lesions consisting of crust formations and alope cia in the skin around the neck from about 4 months of age. Erosion an d ulceration were also observed in advance of the skin lesions. In sev ere cases, the lesions spread to all of the dorsum of the trunk. Skin tissues with or without lesions were studied histopathologically in 41 beige rats comparing with normal skin from 26 age-matched DA rats. Mi croscopically, epidermal lesions consisted of spongiosis, pustules and erosions with crust. Inflammatory cells in pustules consisted predomi nantly of eosinophil, and colonization of gram-positive cocci was occa sionally observed in the surface area. Mites on the epidermis were als o seen in some cases. Dermal lesions were superficial perivascular inf lammatory cell infiltrations of eosinophils, neutrophils and mastocyte s, and edema under the epidermal lesions. Follicles in the alopecic ar ea showed resting stage and atrophic hair germ, but inflammatory chang es were slight. Morphologic characters were very similar to those of c hronic eosinophilic dermatitis or spongiotic dermatitis.