#Downy hair skin

Trichostasis spinulosa – A tuft of vellus hair located in a keratinous sheath is diagnostic.

The terminal hair is usually shed after the birth of the baby upon the return of the hormones to the normal levels. Hormonal fluctuations in pregnant women cause foetal vellus hair to change to terminal hair. Vellus hair can also be found in men with male pattern baldness or with hirsutism. An abundance of vellus hair can develop from an increase in the production of the cortisol hormone in a person with Cushing's syndrome. The unusual growth of vellus hair can be a side effect of some types of disease. This process is called perspiration.Ĭlinical significance Overgrowth More sweat wets the external part of the vellus strand and then evaporates. The sweat on the external part of the strand evaporates.

#Downy hair skin

While a skin pore is open, sweat wets a strand of vellus hair. This insulation regulates body temperature: the vellus hair functions like a wick for sweat.

Vellus hair provides both thermal insulation and cooling for the body. In men, this change in vellus hair also occurs on the face (beard) and the body. At puberty, androgen hormones cause much of the vellus hair to turn into terminal hair and stimulate the growth of new hair in the armpit and the pubic area. The growth cycle of vellus hair is different from the growth cycle of terminal hair. Vellus hair replaces lanugo hair on a human fetus at 36 to 40 weeks of gestation. The Latin language uses the word vellus to designate 'a fleece' or 'wool.' Vellus hair is sometimes colloquially referred to as peach fuzz, due to its resemblance to the downy epidermic growths on the peach fruit. Vellus hair is differentiated from the more visible terminal or androgenic hair, which develops only during and after puberty, usually to a greater extent on men than it does on women. Lanugo hair is a much thicker type of hair that normally grows only on fetuses. Vellus hair is most easily observed on children and adult women, who generally have less terminal hair to obscure it. Each strand of vellus hair is usually less than 2 mm (1/13 inch) long and the follicle is not connected to a sebaceous gland. The density of hair – the number of hair follicles per area of skin – varies from person to person. Exceptions include the lips, the back of the ear, the palm of the hand, the sole of the foot, some external genital areas, the navel, and scar tissue. Vellus hair is short, thin, light-colored, and barely noticeable hair that develops on most of a human’s body during childhood.