hairless

Hairless refers to the absence of visible hair on the body. It can describe a person, an animal, or a breed or population in which fur is greatly reduced or absent. Hairlessness is not itself a disease but can be a trait or symptom of various genetic, hormonal, or environmental factors. In some cases, individuals may be naturally hairless, while in others hair loss occurs due to illness or treatment.

In humans, hairlessness can be congenital (present from birth) or acquired later. Congenital forms include atrichia with papular lesions, a rare genetic condition resulting in near-complete absence of hair. Acquired hairlessness is more commonly described as hair loss or alopecia and can result from autoimmune conditions like alopecia areata, hormonal changes, stress, nutritional deficiencies, burns, or certain medications. Some people experience reduced hair growth without complete baldness.

In animals, several hairless breeds exist, including the Sphynx cat, the Xoloitzcuintli and some varieties of the Chinese Crested dog, and the Peterbald and Donskoy cats. Hairlessness can arise from spontaneous mutations or selective breeding. These animals may have normal or partial hair, and their skin requires special care, including protection from sun exposure, gentle cleansing, and monitoring for skin irritation.