Structural and Pigmentary Characteristics of the Skin in Hairless Dog Breeds

The skin of hairless dog breeds exhibits distinct structural and pigmentary adaptations that compensate for the absence of a protective hair coat. Despite lacking hair, their body surface and core temperatures remain comparable to those of coated dogs. The epidermis of hairless breeds is notably thicker, serving as a compensatory barrier that protects against overheating and excessive cooling. Melanin plays a crucial role not only in pigmentation but also in thermoregulation and antioxidant defense. Genetic mechanisms governing pigmentation involve complex interactions between multiple loci (E, A, B, C, and K), which regulate the production and type of melanin. Hairlessness itself is a dominant genetic trait associated with specific mutations—particularly in the FOXI3 gene—which affect the development of hair, teeth, and other ectodermal structures. However, in the American Hairless Terrier, hairlessness is governed by a different, non-lethal genetic mechanism that does not affect dentition. These findings underscore the intricate interplay between structural adaptation, pigment synthesis, and genetic control that enables hairless dog breeds to maintain physiological balance and effective protection despite the absence of coat.