Histologie features of normal canine and feline skin

Abstract

The skin provides an anatomic barrier and at the same time acts as a principal organ of communication between the animal and its environment. The skin displays remarkable species-dependent anatomic variations in its components, but its general functions are basically preserved throughout the different species. 1–6 The majority of the body surface in dogs and cats is covered by a variably dense haircoat, which exhibits species- and breed-dependent characteristics. It is partially or completely absent in a few feline and canine breeds, such as Devon rex cats, Chinese crested dogs, Mexican hairless dogs, and Abyssinian dogs. 6,7 The hairs provide an additional mechanical and physical barrier and are involved in thermoregulation as well. 6,8 The haircoat itself is often involved in cutaneous disorders and acts as an important mirror for internal diseases. On the other hand, it renders the skin itself less easily accessible for clinical observations. The thickness of the skin varies with species, breed, and body location and ranges from 0.5 to 5 mm in the dog 9 and from 0.4 to 2 mm in the cat. 7 The skin is thickest on the back and dorsal neck, becomes thinner toward the abdomen, and is thinnest in the inguinal and axillary regions. 7,9,10 Its thickness decreases from proximal to distal extremities as well. Histologic features of canine and feline skin in comparison with the human integument are presented according to their anatomic location: (1) epidermis, (2) basement membrane zone, (3) hair follicles, (4) sebaceous glands, (5) sweat glands, and (6) dermis.