Cosmetics can be classified into toiletries, skin care products, fragrance products, and makeup or color products.
These include soaps (cleansers), shampoos, hair rinses and conditioners, hair dressings, sprays and setting lotions, hair color preparations, waving preparations, straightening (relaxing) agents, deodorants, antiperspirants, and sun protective agents.
The purpose of cleansing is to remove sebum that attracts dirt, desquamate the skin, remove airborne pollutants, remove pathogenic organisms, and remove any existing makeup.
The classic cleanser, and the one that has been present for decades, is soap. Soap consists of a substance made up of fatty acid in oil or fat and an alkaline substance. Clear or transparent soap permits better control of the alkaline residue and rinses off more easily. Hard-milled soaps have been considered elegant for many years. Synthetic detergents (syndets) are shaped like soap in bars but consist of anionic surfactants, such as sodium lauryl sulfate that can have a more acidic pH. This makes the syndet easier to rinse off in hard water, and the product can be adjusted to be less irritating to the skin. Special soaps can include medicaments, granules, emollients, or fragrance. Soaps and synthetic detergents have been tested for irritancy, transepidermal water loss, pH, and many other qualities. All of these products have their advantages and disadvantages.
Liquid cleansers have become more popular than ever. To produce a liquid cleanser, water is added and then preservatives (often formaldehyde releasers) later to prevent
pseudomonas infections. These products can become more irritating than bar soap.
Shower gels have become as popular in the United States as they are in Europe. They may have potassium lauryl sulfate as their anionic surfactant or many other ingredients. Many contain the ingredient cocamidopropyl betaine that has become a very common sensitizer. These shower gels appear to rinse off well but may be a little more irritating in some individuals. Perfumed liquid gels using peppermint and pineapple scents have caused many cases of contact and irritant dermatitis in the past seven or so years.
Cleansing cloths impregnated with a body wash-type cleanser are the newest cleansing technology. The fibered facial cloths have a textured side, which induces exfoliation, and a smooth rinse side, which leaves behind petrolatum. This allows cleansing, exfoliation, and moisturization to occur in one product.
Shampoos have three major components—water, detergent, and a fatty material. Like body cleansers, the soap shampoos contain alkali plus oil and fat. Because these may leave a precipitate on the hair shaft with hard water, soap shampoos are rarely used anymore.
Most shampoos are soapless and are made of sulfonated oil. They consist of (l) principal surfactants for detergent and foaming power, (2) secondary surfactants to condition the hair, and (3) additives to complete the formulation and special effects. Because most of the damage to the hair shaft is from chemicals that have a high pH, such as color and permanent or straightening agents, many shampoos are formulated today with an acidic or neutral pH. Because shampoo contains a large amount of water, preservatives (which will be considered later) must be added. Formaldehyde is the most common preservative in shampoo. Because shampoo is only left on the hair for a short period of time, contact dermatitis does not usually occur. Hairdressers, however, are often confronted with that problem. Some of the other additives besides preservatives, such as color, fragrance, and newer essential oils, occasionally can cause allergic reactions.
The major therapeutic agents added to shampoos are tar, salicylic acid, zinc pyrithione, sulfur, and by prescription ketoconazole, cycloallamine, clobetasol, and fluocinonide. It is important for physicians to know that these ingredients do not necessarily harm the hair or strip the color. The formulation of these therapeutic shampoos can contain as many conditioners and beautifying ingredients as nontherapeutic shampoos. They can even be recommended for color-treated, permed, or African-American hair. The formulation must simply be selected for the type of hair (e.g., dry, oily, fine, or coarse).
Because of the trauma to the hair shaft from sun, wind, chemical treatments, and water, conditioners are a necessary hair grooming product for both men and women. The original rinses to remove the soap shampoo film were lemon and vinegar. These substances are still helpful when a person is “roughing it” in the wild or simply not supplied with real conditioners. The other rinses coat the hair shaft so it does not become tangled with the hair shaft next to it. These products contain wax and paraffin, and they allow the hair to shine without static cling. Balsam is a product in that category.
The major conditioners for traumatized hair are cationic surfactant conditioners. Quaternary ammonium compounds, especially stearalkonium ammonium chloride, have been used for many years to make the hair manageable. It is possible to attach a polymer (such as polyvinylpyrrolidone) or other film formers to the quaternary ammonium compounds. These not only condition the hair, they add extra volume or body. There are even conditioners that contain sunscreens to protect the hair color. Occasionally, too-frequent use of any of these conditioners can cause a buildup on the hair shaft so that the hair becomes too soft. This can be counteracted with an anionic shampoo to strip off the buildup so that the hair is fresh and more easily managed.
Protein-based conditioners consist of amino acids and small polypeptide fragments of hydrolyzed protein. These can be incorporated into the cortex of the hair shaft when the hair has just been processed with color or permanent waving or has been under a heat cap. This is advisable for hair that has been damaged through processing, wind, swimming, or sun. There have been reports of contact urticaria to the protein components of hair conditioners such as quaternary derivatives of hydrolyzed bovine collagen protein.
Styling aids consist of lotions, gels, mousses, or hair spray. Most of these products contain water, copolymers, polyvinylpyrrolidone, quaternary salts, and fragrance. They waterproof the hair so that perspiration or mild rain does not upset the style.
Permanent Waves and Relaxers
The three natural wave patterns of hair are straight, wavy, and kinky. To allow the hair to be curled differently, straightened, or become slightly wavy, a chemical reaction involving the breaking of disulfide bonds of the hair with heat, high pH, or thioglycolates must take place. For straightening, it is broken with sodium hydroxide, guanidine hydroxide, lithium hydroxide, heat, or thioglycolates. The hair is placed over rods or curlers, treated with the appropriate chemical until the shape of the hair shaft is changed, then neutralized with hydrogen peroxide with sodium perborate or potassium bromate. Some of the disulfide bonds are never repaired, so this process can be very hard on the hair shaft.
The mildest form of hair curling is the acid permanent—glycerol monothioglycolate. This is appropriate for fine or for color-treated hair. There are more cases of allergic contact dermatitis due to this chemical than to the other curling
or straightening agents. This permanent wave must be administered in a professional salon.
The midstrength permanent wave is ammonium thioglycolate. This can be used on healthy hair for curling or on kinky hair for straightening. This may be performed at home because of its safety.
The strongest chemicals for these procedures are for resistant kinky hair and include lye (with the higher pH) or sodium, lithium, or calcium hydroxide. Professionals must apply these products. If the chemicals are left on too long, the hair shaft may break. They can also burn the skin.
The most common hair loss in African Americans today is central centrifugal cicatricial alopecia (CCCA). Often this is caused by straightening procedures or the frequent use of extensions. It is important for the dermatologist to ask specific questions regarding these procedures. A good physician must recognize that these procedures must take place. He or she must just advise the patient about the strength of chemicals, frequency of use, or the exact form of extensions the patient is using. CCCA can be treated with topical potent steroids if caught early enough. If not, intralesional steroids may be given. Another cause of breakage of hair in these patients is straightening the hair too frequently. If the hair at the nape of the neck is broken at about 1 cm length, the patient may be straightening his or her hair every 6 weeks instead of 8 weeks as recommended.
The five major types of hair coloring are temporary, gradual, natural, semipermanent, and permanent.
The temporary colors are textile dyes. These dyes lie on the top of the cuticle and come off easily with perspiration or rain. Their advantage is they let the individual try a color and not cause any permanent change. These are safe and do not cause allergic reactions. The disadvantage is that the color can come off easily onto one’s face or clothes.
The gradual colors consist of metallic salts. The hair can go from gray to brown or black by the action of lead acetate and sulfur. These salts precipitate on the outside of the hair shaft and allow a gradual change in color. Unfortunately, the hair looks very lusterless and can have a characteristic sulfur odor. The metal precipitate also precludes any other hair processing, such as permanent or other coloring procedures. The hair must grow out or have a stripping process before other cosmetic procedures may take place.
Natural coloring with henna from Lawsonia inermis is rarely used anymore. This is a vegetable dye that has no concern regarding carcinogenicity. It imparts red highlights to hair. This substance can precipitate asthma and allergies. Henna also stains gray hair an unpleasant orange color.
Semipermanent dyes are a nice first step for a person going from gray to a darker color. The active ingredients are low molecular weight dyes specifically synthesized for hair coloring. Because the molecules are small, they can penetrate the cuticle and go into the cortex. These dyes leave the hair shiny and attractive. Because these same molecules can slip out of the cuticle just as easily, the color only lasts for four to six shampoos. These dyes have low allergenicity, are easy to apply, and cause only minimal hair shaft damage. Because there is no peroxide used, the colors can only go darker, not lighter.
By far the most common products for hair color in men and women today are the permanent hair color dyes. In permanent or oxidative hair coloring, the formation of colorless molecules from their precursors occurs inside the cortex as a result of oxidation by hydrogen peroxide. The reaction is p-phenylenediamine + H2O2: amines: amines + couplers : indo dyes. The indo dye molecules are so large that they cannot slip out of the cortex of the hair shaft. This color lasts for 4 to 6 weeks, until the new growth of scalp hair at the base becomes visible. The correct procedure then is simply to color the 1 or l.5 cm of new growth.
Frosting or highlighting of the hair consists of taking strands of the hair and selectively bleaching them with the same procedure using 30 or 40 volumes percent for hydrogen peroxide (instead of 20 volumes percent, as in normal color).
For a real brunette to become a platinum blond, two processes must be used: first, a removal of all the color with peroxide, and second, a dying of the hair as outlined previously. This is the most traumatic procedure that can be performed on the hair. With all of these chemical processes, the hair can be broken off at any point on the shaft. Table 7-1
provides a summary of these color techniques.
Skin Care Products
According to the North American Contact Dermatitis Group, skin care products cause the greatest number of adverse reactions in cosmetics. These can be irritant dermatitis, allergic dermatitis, acne cosmetica, or folliculitis. To understand these products more thoroughly, it is important to study the types of ingredients compounded for these products. These consist of emollients, humectants, surfactants, preservatives, and fragrance.
Emollients are film-forming materials that add substance to cosmetic preparations and function on the skin to retard water loss. Six categories of emollients are hydrocarbons, waxes, natural lipid polyesters, lightweight esters and ethers, silicone, and ceramides.
The hydrocarbons that are most familiar are mineral oil and petrolatum. Because these products contain no water, there is no need to add preservatives to them. It has been shown by tagging C+ atoms that petrolatum actually penetrates into the intercellular substance of the epithelium. These hydrocarbons are heavy and may not be as aesthetically pleasing as other moisturizers. In the temperate zones in the winter, however, they are ideal for hands, feet, and other very dry areas on the body. They probably are too occlusive for facial skin. Cosmetic grade petrolatum has been a more frequently used ingredient of facial cosmetics in the last few years. This grade is noncomedogenic.
TABLE 7-1 ▪ Coloring Products and Their Key Characteristics*
Type of Dye
Site of Action
Temporary color rinses
Minimal; apply and dry
High molecular weight acid dyes as used in textiles, and certified food colors in a hydroalcoholic suspension
Surface of shaft
Poor; removed by shampooing
Single- or multiple-use package; more viscous than no. 1 to prevent dripping off hair
Moderate; apply to freshly shampooed hair and leave in place for 15-40 min; skin patch test required
Low molecular weight dyes: nitrophenylene-diamines, nitroamino-phenols, aminoanthro-quinones in shampoo vehicle or a solvent system
Covers gray; one to three shades on dark side of normal hair colo
Penetrates to cortex
Gradually lost through three to five shampoos
Permanent oxidation type
Two-unit system for mixing just before use
Moderate; skin patch test required
Several classes of dyes including PPD† intermediates in an alkaline peroxide “shampoo”
Covers gray; two or three shades on each side of normal
Permanent; new growth touch-up every 4-8 weeks
Same as above
Professional attention necessary
As above, but hair must be previously decolorized (stripped)
Moderate; hair breakage; local and systemic peroxide reactions
Metallic salts particularly lead, in solution, cream, or pomade form
Discolors hair only
Surface and some beneath cuticle
As long as product is used regularly
Negligible; a public health problem; incompatible with other chemical hair services
For all practical purposes, this does not exist and is not available.
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