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Laser Hair Removal Glossary of Terms

Alpha hydroxy acid - AHAs are chemical compounds that are commonly used as exfoliants. They are often used after laser hair removal treatment to lower the risk of ingrown hairs. Common AHAs are citric acid, lactic acid and glycolic acid.

Anagen - The anagen stage of the hair growth cycle is the active stage. During the anagen phase, hair grows about a half an inch every 28 days. Hair on the scalp stays in the anagen phase for two to six years.

Analgesics - Analgesics are used to reduce pain. Laser hair removal clients are often given analgesics before the procedure to reduce pain.

Androgen - Androgen is a masculine sex hormone that causes hair growth in a typically masculine pattern. Testosterone is the most common androgen.

Bikini line - The bikini line is a line noted in the hair removal industry to denote the amount of hair removed so that it is not exposed by underwear or a bikini swimsuit.

Catagen - The catagen is the brief stage during the hair growth cycle that occurs after the anagen stage. This stage lasts about two weeks.

Club hair - Club hair is in the final stage of the hair growth cycle where hair has been released from the hair follicle but has yet to be shed.

Cuticle - The cuticle is the outer layer of the hair strand. It locks the hair into the hair follicle.

Depilation - Depilation of the removal of the hair above the skin surface. This provides short term, temporary hair removal. Shaving is the most common form of depilation, but chemical depilatories are also common.

Dermal papilla - The dermal papilla is a small bulge at the root of the hair. It is one of the main targets when attempting to achieve permanent hair removal.

Dermis - The dermis is the layer of skin located under the epidermis but above the layer of subcutaneous fat. It is made up of lymph vessels, blood vessels, sweat glands, elastic fibers, collagen bundles, hair follicles and fibroblasts. Hair grows from the dermis. The skin's firmness is determined by the dermis.

Dermatitis - Dermatitis is redness and irritation of the skin. Eczema is a severe form of dermatitis. Scalp dermatitis is common in the form of dandruff. Dermatitis can be caused by an allergic reaction to chemical substances. It can also be caused by certain forms of hair removal. It can be treated with hyrdrocortisone ointment. People who suffer from preexisting dermatitis may not be ideal candidates for laser hair removal.

Depilatory - A depilatory is a chemical used for temporary hair removal. Sulfide is a common chemical depilatory as is calcium thioglycolate. Keratin is weakened by the chemicals, making it easy to scrape the hair off when it appears above the skin line. Depilatories can cause severe skin irritation and have a foul odor.

Distorted hair follicles - Distorted hair follicles are rare. The follicles do not go straight down into the dermis, making it difficult to target the follicle for laser hair removal or electrolysis.

Edema - Edema is swelling of the extremities. It can be a side effect of laser hair removal treatment.

Electrolysis - Electrolysis is the process of sending an electric current into a hair follicle. Electrolysis deadens the follicle and slows hair growth. It's use has decreased over time due to the increasing popularity of laser hair removal.

Epidermal cooling - Epidermal cooling reduces pain during laser hair removal and can reduce the risk of side effects. There are four types of epidermal cooling: air cooling, clear chilled gel, cryogenic spray and contact cooling in which the skin is cooled by circulating water.

Epidermis - The epidermis is the top layer of the skin. It is made up of squamous cells, melanocytes, basal cells and keratinocytes. It forms a waterproof, protective barrier between the body's surface and the outside world. The epidermis contains no blood vessels. It receives nutrients from the dermis in a process called diffusion. The epidermis is broken down into many layers. It is made up of over 25 layers of dead skin cells.

Epilation - Epilation is the removal of the entire hair, including the part of the hair that is below the skin. Epilation is a longer lasting form of hair removal. Examples of epilation are laser hair removal, waxing and tweezing.

Erythema - Eythema is a redness of the top layer of skin. It is caused by the dilation or congestion of the capillaries. It is a common side effect of laser hair removal. It can be treated by applying ice packs.

Eschars - Eschars are dried fluid that oozes from skin after electrolysis or lase hair removal.

Estrogen - Estrogen is the female sex hormone that has been linked to an increase is the growth of hair. There are three types of estrogen; estrone, estriol and estradiol.

Folliculitis - Folliculitis is an inflammation or infection of a hair follicle. It is caused when the hair follicle suffers damage during shaving or friction caused by clothing and is then contaminated by bacteria.

Hair Follicles - A hair follicle is a cylinder of squamous cells that is located in the dermis layer of the skin. Hair is created in the hair follicle by old cells packing together. The sebaceous gland, a small glad that produces oil, is found inside the follicle. It is found everywhere on the body except on the bottoms of the feet and the palms of the hand. Laser hair removal disables the hair follicle temporarily.

Hirsuitism - Hirsuitism is a female condition where excess hair grows in a male pattern. Women may develop excess hair growth on the lower abdomen or on the face or other areas where dark coarse hair is usually sparse or non existent. Hirsuitism can be caused by medications, genetics and hormonal problems.

Hyper pigmentation - Hyper pigmentation refers to a condition in which the skin is darker than the surrounding tissues. It can be caused by skin injuries, acne, sun damage and conditions like Cushing's Disease, celiac disease and Addison's disease. It can also appear temporarily on the abdomen of pregnant women in a condition called linea nigra.

Hypertrichosis - Hypertrichosis is the excessive presence of hair in either an abnormal or normal pattern of growth. It can be caused by genetics, tumors, malnutrition, metabolic problems or medication. Uncontrolled hypertrichosis is usually referred to as Werewolf Syndrome.

Hypopigmentation - Hypopigmentation is the absence of skin color. It is a potential side effect of laser hair removal. It is caused by the depletion of melaocyte.

Intense Pulsed Light - IPL is a method of hair removal that uses a xenon flash lamp. Beauticians and other non-medical personal may remove hair using Intense Pulsed Light. It is growing in popularity because it is faster and cheaper than traditional laser hair removal. IPL can also be used to treat rosacea outbreaks and to reduce the appearance of vascular birth marks.

Joule - A joule is a measurement of the energy that a laser puts out. It is usually expressed cm2 (per square centimeter) It was named after James Prescott Joule, an English physicist.

Keloid - A keloid is a scar made up of dark, raised skin tissue. It is more common in people of middle eastern or African origin. It occurs from excessive growth of scar tissue over a skin injury that has healed. Keloids can cause pain or severe itching. Keloids can be removed, but they can recur.

Keratin - Keratin is a form of protein that makes up skin, finger nails and hair. It is one of the toughest substances in the body.

Laser - Lasers are narrow beams of concentrated light. Lasers serve a variety of purposes, including the treatment of skin disorders and the removal of unwanted hair.

Laser Circles - Laser circles are areas on the skin that appear after treating excessively tanned skin with a laser light. People with deep tans should not be treated for hair removal with laser due to the risk of laser skin burn or laser circles.

Laser Hair Removal - Laser Hair Removal uses laser lights to remove hair below the skin line. The hair follicle is disabled by treatment with lasers, resulting in slowed hair growth. Laser hair removal first became available commercially in the mid nineties. Laser hair removal can be accomplished with much less pain that previous long term hair removal methods. Hair removal is long term and in many cases can be permanent. It is a one of the most popular methods of hair removal today.

Melanocytes - Melanocytes are specialized cells in the epidermis that produce the substance melanin which gives the skin, freckles and moles their color. It is located in the bottom-most layer of the epidermis later of the skin.

Melanin - Melanin is a natural substance that gives hair and skin its color. Two types of melanin appear in the body. Eumelanin gives color to dark hair while pheomelanin gives red and blond hair its color. Only eumelanin can absorb laser light, so red and blond hair can not be removed with a laser.

Multiple sessions - Multiple sessions are counted as more than one session with a laser hair removal expert. Effective, long term laser hair removal may require multiple sessions before optimum results are achieved.

Nevus - A nevus is a type of benign mole. All moles should be checked by a doctor prior to beginning laster hair removal. There are many types of nevi. Some nevi are incompatible with permanent hair removal.

Over Treatment - Over treatment is hair removal treatments that are so aggressive that they can cause permanent or temporary skin damage.

Q-Switched - Q-Switched is a type of laser that is sometimes used during hair removal. It is not thought to be as effective as normal or long pulsed lasers.

Perifollicular edema - Perifollicular edema is swelling in the areas around the hair follicles. It can be a temporary side effect of laser hair removal. It is usually mild and will go away in a few hours after laser hair removal. Treatment with a cooling mechanism can combat edema.

Pseudofolliculitis barbae - Pseudofolliculitis barbae is commonly known as shaving bumps and ingrown hairs. This condition can be successfully prevented by removing body hair with a laser hair removal system.

Psoriasis - Psoriasis is a disease which can cause scaly red patches to appear on areas of the body. They are caused by excessive skin production. Psoriasis is chronic, but it is not contagious. Patients affecte by psoriasis are not candidates for laser hair removal.

Re-growth - Re-growth occurs when hair that has been removed grows back. Laser hair removal can extend the period of time between re-growth cycles. It can also make regrown hair finer and lighter.

Telogen - The telogen phase is a period of time in which the hair follicle rests. No hair grows during the telogen phase. Telogen hairs shed frequently. It is normal to lose up to 100 telogen hairs daily.

Terminal hair - Terminal hair is hair that is longer, more coarse and fully developed. It is usually found in the beard, the torso in men, legs, the underarm area, the scalp and the bikini line. This is the type of hair that is most frequently targeted for laser hair removal. Hair that is softer or lighter is does not respond well to laser hair treatment.

Vascular lesions - Vascular lesions are caused by the malformation or the rupture of arteries and veins near the surface of the skin.

Vellus Hair - Vellus hair is hair that is soft, very fine, non-pigments and short. It is usually found on the body or the face. It is usually less than two millimeters long. Vellus hair grows from follicles that aren't connected to sebaceous glands. Laser hair treatments are often ineffective in removing this type of hair. Vellus hair will respond to electrolysis.

Vitiligo - Spots on the skin that lack pigment. The areas may turn pale or white. This condition usually has an onset after adolescence. Vitiligo is a complex condition and its cause is not readily understood. Skin effected by vitiligo should not be treated by laser hair removal due to the increased risk of laser skin burns.