Histopathology of the skin from the outer ear canal in a Chorioptes -infested moose. A: Marked epidermal hyperplasia with prominent rete ridges (acanthosis) and orthokeratotic hyperkeratosis. HE. B: Acanthotic epidermis with multifocal crust formation (arrows) and mixed inflammation in dermis. HE. C: Haemorrhagic crust with embedded cross-sectioned mite (arrow), on epidermis. HE. D: Dermal inflammation, showing lymphocytes, plasma cells and some macrophages with a perivascular to interstitial distribution. HE. E: Immunohistochemistry for CD3 F7.2.38 (T-lymphocytes stained brown), showing perivascular infiltrate of T-lymphocytes and plasma cells in deeper parts of the dermis. En-Vision+® with haematoxylin.