Hair Salons Concord NH
By Stephen M. Schleicher, MD, Director, DermDOX Center for Dermatology
The scalp contains approximately one hundred thousand hairs. Each hair attains a maximum length and then enters a resting stage, following which, it falls out. Unlike certain animals, which shed their entire outer layers at once, human’s have hairs that act independently; normal human hair loss occurs in random fashion and is quite inconspicuous. Some one hundred scalp hairs are regularly shed on a daily basis (This may seem like a large number, but it represents only one-thousandth of the total scalp hair).
Hair grows at different rates depending on its location. Scalp hair expands at a rate of one-hundredth of an inch per day; in other words, one hundred feet of new hair is manufactured on a daily basis. Each scalp hair is capable of growing for three to ten years. This is in contrast to the hair of the armpits and eyebrows, which has a growth period of less than 1 year; these hairs grow to fixed lengths and then enter into a prolonged resting period.
The hair that we look at, fondle, and spend so much time and money on is merely dead tissue. Living hair is produced from protein under the skin within a structure called the hair follicle. The hair is no longer alive by the time it reaches the surface.
Each follicle is attached to an oil gland and is surrounded by nerves and muscles. The muscles are very sensitive to cold and contract on stimulation, pulling the hair follicle and wrinkling the skin surface. This action gives rise to the tiny raised pimples known as goose bumps.
Hair differs in both amount and consistency among the various races. Whites are the hairiest, followed by blacks, with Asians being the least hirsute. Asians have the straightest hair, while blacks have the curliest.
Hair color depends on the number of pigment cells (melanin) within the hair shaft. Blond hair contains few pigment cells, and the snow-white hair of the elderly has virtually none. Red hair is due to an iron-bearing pigment.
As we age, so does our hair. Aged hair is grey or white. To date, despite advertising claims touting melatonin, copper blockers, and vitamins, the only effective treatment is hair dye. But there is hope. Some of the aged follicles from which hair grows still contain miniscule amounts of pigment cells, and recent evidence points to a buildup of hydrogen peroxide in older follicles which prevents these cells from producing pigment (melanin). Finding a way to decrease hydrogen peroxide within the follicle may reverse the graying process.
Reports periodically surface that hair-coloring agents promote cancer. Fortunately, this does not appear to be the case, and if there is a risk, it is quite minimal. Hair dyes can however trigger allergic reactions, hence the warning on package inserts to test the skin prior to each application. Allergic reactions do appear to be on the rise as more, and younger, individ...