Eosinophilic Dermatitis and Sebaceous Adenitis in the Head and Neck of a Cat

Abstract

A 2-year-old castrated male cat presented with alopecia and itching on the head for approximately two months. Macroscopically there were ulcerative lesions with reddish crusts and alopecia with dander and follicular casts on the skin of top of the head and neck. Histologically, there were diffuse infiltrates of eosinophils and macrophages from the superficial dermis to subcutaneous tissue. In the inflammatory lesions, collagenolysis with eosinophilic inflammation called flame figures was occasionally observed. In the alopecic lesions, there was mild epidermal hyperplasia with orthokeratotic hyperkeratosis. In addition, multiple sebaceous glands were surrounded by CD3-positive T cells and macrophages. Based on these histological findings, the cutaneous lesions of the present case were diagnosed as eosinophilic dermatitis and sebaceous adenitis.