Cleansers

The development of soaps designed to cleanse the skin has been the single most important advance in decreasing disease worldwide. Even though soap is ubiquitous in the developed world, one of the main goals of global health organizations is to introduce the concept of cleansing with soap to regions of the world where contagious diseases run rampant. In basic chemical terms, soap is a fatty acid salt resulting from a reaction between a fat and an alkali . The soap solubilizes sebum and environmental dirt, such that it can be rinsed away with water. The mechanics of rubbing the soap over the skin with the hand or a bathing implement results in the physical removal of desquamating scales, bacteria and fungi from the skin surface. In high-income countries, where bathing has become a daily ritual, excessive use of soap has resulted in dermatologic conditions such as xerotic eczema. This has led to the development of cleansers with skin conditioning benefits that are chemically not true soaps, and they are referred to as detergents.

Cleansers, whether formulated as bars or liquids, can be divided into three basic types: soaps, syndets and combars ( Table 153.1 ). True soaps are composed of long-chain fatty acid alkali salts with a pH of between 9 and 10. This alkaline pH raises the pH of the skin following cleansing, resulting in stratum corneum barrier disruption and the resultant feeling of tightness following bathing. Alkalinization of the skin disrupts the natural acid mantle, which may be significant in dermatitic skin. Recognition of the need to preserve skin pH at 5.4 led to the development of syn thetic det ergents, known as syndets, such as sodium cocoyl isethionate. Syndet cleansers, also known as beauty cleansers, contain less than 10% soap and are designed with a pH of 5.5–7.0 in order to minimize cutaneous alkalinization . The third type of cleanser, known as a combar, is composed of an alkaline soap to which surface active agents with a pH of 9–10 have been added. Combars are milder cleansers than true soaps, but induce more thorough cleansing than syndets. For example, true soap is a good cleansing choice for excessively oily or dirty skin, while a combar is a good cleanser for normal skin with a moderate amount of environmental dirt. Syndets would be the least damaging to the cutaneous barrier in persons with xerosis or any form of dermatitis.

The many brands of cleansers currently on the market fall into one of the three aforementioned groups, yet there must be something unique, for marketing purposes, about each cleanser. The unique aspects of each cleanser are created through the addition of specialty additives ( Table 153.2 ). Common cleanser additives include various fragrances as well as foaming agents designed to alter the aesthetics of the lather, but the most dermatologically relevant additives are antibacterial agents. The most widely used antibacterial in both bar and liquid cleansers used to be triclosan , but is now benzalkonium chloride. Triclosan works by blocking lipid synthesis within the bacterial cell wall, thus decreasing the skin biofilm bacteria count and reducing odor. However, in 2016, triclosan was banned in the US as an ingredient in consumer antiseptic washes.

Another important dermatologic need with regard to skin cleansing is minimization of skin barrier dysfunction. Unfortunately, surfactants cannot distinguish unwanted sebum and oil-soluble dirt from intercellular lipids. Thus, increases in transepidermal water loss are typically noted in direct proportion to the cleansing ability of the cleanser. An attempt to provide cleansing and barrier restoration in the same product has led to the development of body washes. Since body washes are liquids, incorporating both hydrophilic and lipophilic ingredients emulsified into a single phase, it is possible to cleanse and moisturize simultaneously while allowing for rinsing away of the surfactants. Body washes must be used with a puff to introduce both water and air into the cleanser emulsion in sufficient quantity to allow cleansing and moisturization to occur. The syndet detergents, primarily ammonium laureth sulfate, solubilize oil-soluble dirt into the rinse water for removal during the cleansing phase when the body wash concentration is high and the water concentration low, while occlusive moisturizing substances (e.g. petrolatum) and emollients (e.g. soybean oil) are left behind to retard transepidermal water loss and improve skin smoothness during the rinse phase when the body wash concentration is low and the water concentration is high.

Other cleanser variants for persons with dry, dermatitic skin include lipid-free, non-foaming cleansers and cold creams. These products are excellent at removing cosmetics and low levels of environmental dirt. Lipid-free cleansers are non-foaming, soap-free liquid products applied to dry or moistened skin, rubbed to produce minimal lather, and rinsed or wiped away. They possess low surfactant capabilities, and they can only remove bacteria through mechanical means, yet they are important in persons with barrier disruption . The classic cleanser for dry, dermatitic skin is cold cream, which combines the effect of a lipid solvent, such as wax or mineral oil, with detergent action from borax . However, not all formulations of cold creams contain borax.

Occasionally, a dermatologic need arises for specialty cleansers designed to offer a skin benefit beyond pure removal of sebum and environmental dirt. For example, it may be desirable to induce corneocyte disadhesion in older patients requiring an exfoliant cleanser. This can be accomplished through the addition of chemical exfoliants, such as salicylic acid or glycolic acid, to the cleanser formulations discussed previously. Exfoliant cleansers containing benzoyl peroxide or salicylic acid are sometimes used as an adjunct in topical acne treatment. Exfoliation can also be induced mechanically through the incorporation of fine abrasive particles (such as polyethylene beads, aluminum oxide, ground fruit pits, or sodium tetraborate decahydrate granules) in a liquid syndet cleanser to remove skin scale. Lastly, mechanical exfoliation can be encouraged through the use of specially woven face cloths, designed to remove skin scale without inducing epidermal damage.

The development of novel detergents and cleansing specialty additives has created a confusing plethora of consumer products, yet the goal remains the same: to allow adequate skin hygiene without barrier damage. Our next concern is the discussion of moisturizers, designed to replace skin sebum and natural moisturizing factors in instances where the stratum corneum barrier has been damaged from exuberant cleansing.

Moisturizers

The term “moisturizer” is somewhat misleading to the consumer, who assumes that the cream or lotion actually puts moisture or water back into the skin . Moisturizers do not put water back into the skin externally, nor do they get incorporated into the intracellular lipids. Moisturizers simply attempt to retard transepidermal water loss and create an optimal environment for restoration of the stratum corneum barrier . The optimal water content for the stratum corneum is between 10% and 30%, depending on the measurement technique employed, and moisturizers can function to raise the cutaneous water content through occlusion or humectancy via a variety of active agents ( Table 153.3 ) .

Occlusive moisturizers prevent evaporative water loss to the environment by placing an oily substance on the skin surface through which water cannot penetrate, thus replenishing the stratum corneum moisture by water movement from the lower viable epidermal and dermal layers . There are many different classes of chemicals that can function as occlusive moisturizers , for example, hydrocarbon oils and waxes (petrolatum, mineral oil, paraffin, squalene), silicones (cyclomethicone, dimethicone), vegetable oils (castor oil, corn oil, grape seed oil, soybean oil), animal oils (mink oil, emu oil), fatty acids (lanolin acid, stearic acid), fatty alcohols (lanolin alcohol, cetyl alcohol), polyhydric alcohols (propylene glycol), wax esters (lanolin, beeswax, stearyl stearate), vege­table waxes (carnauba wax, candelilla wax), phospholipids (lecithin), and sterols (cholesterol, ceramides) .

The most effective occlusive moisturizer is petrolatum, since it reduces transepidermal water loss by 99% . Total occlusion of the stratum corneum is undesirable, since transepidermal water loss is the cellular signal that initiates barrier repair and the resulting synthesis of intercellular lipids . Complete cessation of transepidermal water loss results in no barrier repair, allowing water loss to return to its pretreatment level once the complete occlusion has been removed . Petrolatum allows barrier repair while permeating throughout the interstices of the stratum corneum .

Another technique for rehydrating the stratum corneum is the use of humectants. Humectants are substances that attract moisture; they include glycerin, honey, sodium lactate, urea, propylene glycol, sorbitol, pyrrolidone carboxylic acid, gelatin, hyaluronic acid, and some vitamins and proteins . The body utilizes hyaluronic acid and other glycosaminoglycans in the dermis as biologic humectants to prevent desiccation of the skin. Humectants can only hydrate the skin from the environment when the ambient humidity exceeds 70%. Consequently, rehydration of the stratum corneum generally occurs by water that is attracted from the deeper epidermal and dermal tissues. Most moisturizers combine both occlusive and humectant moisturizing ingredients, since water drawn by a humectant to a damaged stratum corneum barrier will be lost to the atmosphere unless trapped by an occlusive . Humectants also help to improve the smoothness of xerotic skin by inducing corneocyte swelling and minimizing voids between the desquamating corneocytes .

In summary, remoisturization of the skin must occur in four steps:

• •
  

  initiation of barrier repair (see Ch. 124 )

  
  
• •
  

  alteration of surface cutaneous moisture partition coefficient

  
  
• •
  

  onset of dermal–epidermal moisture diffusion

  
  
• •
  

  synthesis of intercellular lipids .

Moisturizers attempt to increase stratum corneum water content through the principles of occlusion and humectancy. The discovery of aquaporin 3 channels in the skin and their modulation by glycerin and urea has increased research into osmotic cell balance as another mechanism for moisturization.

Astringents

Occasionally, patients use skin care products that either correct the deficiencies of the cleanser or supplement the effects of the moisturizer. These products are known as astringents or toners (see Table 153.1 ). They are used after cleansing but before moisturizing, and they are left on the face following use. Astringents are usually liquids wiped over the face with a cotton ball. Originally, astringents were intended to remove soap scum left behind on the face from the use of lye-based soaps and hard water. If left behind, this soap scum could cause irritant contact dermatitis. The original astringents were fragranced isopropyl alcohol or propylene glycol solutions designed to remove oil-soluble residue. The development of synthetic detergents and treated water has made this original intent obsolete, yet astringents remain popular.

Currently, astringents are used to remove the oily residue left behind after cleansing of the face with lipid-free cleansers or cleansing creams, discussed previously. Oily complexion astringents are formulated to remove any remaining sebum from the face following synthetic detergent cleansing or to deliver keratolytics, such as salicylic acid, glycolic acid or witch hazel. Some astringents designed for dry skin contain a humectant liquid moisturizer, such as propylene glycol or glycerin, and skin soothing agents, such as allantoin, guaiazulene or quaternium-19 . A complete cosmetic-counter facial treatment routine involves a cleanser followed by an astringent and then a moisturizer. Once the skin has been prepared in this manner, colored cosmetics are applied.

Facial foundations

Application and cutaneous effects

Facial foundations must be evenly applied to create the optimal cosmetic appearance and achieve the secondary benefit of sun protection. The iron oxide pigment and other covering agents, e.g. titanium dioxide, zinc oxide and kaolin, are physical particulates that block both UVA and UVB radiation (see Ch. 132 ). A facial foundation without any added organic sunscreen ingredients, such as ecamsule, octyl methoxycinnamate, oxybenzone or avobenzone, usually has a sun(burn) protection factor (SPF) of at least 4. Facial foundations that have greater coverage in order to camouflage underlying pigmentation defects usually possess an SPF of at least 8. The inclusion of additional sunscreen agents to the facial foundation can raise the SPF to 15. Thus, facial foundation is an excellent, cosmetically elegant facial photoprotectant.

An even, cosmetically acceptable application of facial foundation begins with a proper color match to the skin at the jawline and application with the fingertips. A dab of foundation should be placed on the forehead, nose, cheeks and chin, and blended with a light circular motion until it is evenly spread over the entire face, including the lips. Finally, a puff or sponge should be used, stroking in a downward direction, to remove any streaks and to flatten vellus facial hair. Special care should be taken to rub the foundation into the hairline, over the tragus, and beneath the chin. Foundation should also be blended around the eyes, and it may even be applied to the entire upper eyelid if desired. The foundation should be allowed to set or dry until it can no longer be removed with light touch. If additional coverage is desired, a second layer of foundation can be applied.

The most common adverse dermatologic effect related to the use of facial foundation is a condition patients describe as “breakouts”. Patients typically note small perifollicular papules 48 hours after using a new facial foundation. The appearance resembles that of acne; however, the 48-hour time course is inconsistent with a diagnosis of acne. This condition may represent a perifollicular irritant contact dermatitis, since facial foundations tend to migrate to the follicular ostia as they mix with eccrine secretions and sebum, which break down the cosmetic film ( Fig. 153.1 ). This observation may explain why facial foundations that have been found on clinical testing to be non-comedogenic and non-acnegenic cause acneiform eruptions in individuals with self-diagnosed sensitive skin. Overall, however, facial foundations are an infrequent cause of dermatologic problems.

Migration of iron oxide particles in facial foundation to follicular ostia.

As seen by video microscopy (400×), this migration tends to occur as sebum and eccrine secretions mix with the cosmetic film.

Powders

One of the ways of preventing migration of facial foundation, improving its sun protective capabilities, and increasing oil absorption, is to apply powder over the foundation. Facial powders contain predominantly talc (hydrated magnesium silicate) and increased amounts of covering pigments. The covering pigments used in face powder are listed in order of increasing opaqueness in Table 153.5 . It is generally accepted that the optimum opacity is achieved with a particle size of 0.25 mcg. Black dermographism from earrings and rings can result when face powders contain ingredients, e.g. zinc oxide, that are harder than platinum, silver or gold.

Facial powders usually also contain magnesium carbonate and/or kaolin (hydrated aluminum silicate) to absorb oil and perspiration. Full-coverage face powders with increased pigments and light-reflective particles are usually packaged as a cake in a compact and applied to the face with a puff, loose in a jar and dusted over the face with a brush, or stroked over the face from an automatic brush dispenser. These face powders with increased pigments can be used as a facial foundation and are known as mineral make-ups. They are recommended for persons with sensitive skin and rosacea as they contain no liquids, fewer preservatives, and fewer ingredients. As a result, there is decreased potential for allergic and irritant contact dermatitis. Specially pigmented powders are used to redden the cheeks, known as blushes, and to color the eyelids, known as eye shadows.

Eye shadows

Eye shadows are similar to powder blushes in formulation and surface characteristics, except that the color variation is broader, but limited in the US by the Food and Drug Administration (FDA) to the purified natural colors or inorganic pigments listed in Table 153.6 . Eye shadow can be used to camouflage misshapen eyes, provide sun protection to the upper eyelid, and minimize the appearance of unwanted periorbital pigmentation. Eye shadows are a common concern to dermatologists, since they may be responsible for eyelid dermatitis. They may contain the same light-reflective particles as blushes and cause pruritus of the eyelids due to irritant contact dermatitis until discontinued ( Fig. 153.2 ).

Table 153.6

Pigments allowed by the US Food and Drug Administration (FDA) in eye shadow cosmetics.

PIGMENTS ALLOWED BY THE US FDA IN EYE SHADOW COSMETICS

Iron oxides Titanium dioxide (alone, or combined with mica) Copper, aluminum and silver powder Ultramarine blue, violet and pink Manganese violet Carmine Chrome oxide and hydrate Iron blue Bismuth oxychloride (alone, or on mica or talc) Mica

 

Upper eyelid dermatitis.

Upper eyelid dermatitis may be exacerbated by the use of heavily pigmented, light-reflective eye shadows.

In one series, the North American Contact Dermatitis Group determined that 12% of cosmetic reactions occurred on the eyelid, but only 4% could be linked to eye make-up use . When allergic contact derma­titis is due to eye shadows, the most common culprits are the red pigments used in pinkish eye shadows. Unfortunately, it can be difficult to determine the etiology of allergic contact eyelid dermatitis with routine patch testing , since many substances can be transferred to the eye area by the hands, complicating the dermatologic evaluation . However, eye shadows are a rare cause of eye infections, since the dry powder cake does not support bacterial growth.

Mascaras

Mascaras are eyelash cosmetics, as opposed to eye shadows, which are eyelid cosmetics. Mascaras are designed to color, camouflage, elongate and thicken the eyelashes, which are the frame to the eyes. They must be carefully formulated to allow easy and even application without smudging, irritancy or toxicity. Some of the coloring agents employed include iron oxide to produce black, ultramarine blue to create navy, and umber, burnt sienna or synthetic brown oxide to create brown .

Most modern mascaras are formulated as liquids, then stored in a tube with a multitufted applicator brush or comb. The applicator is inserted into the tube between uses, providing numerous opportunities to inoculate bacteria into the cosmetic. The most dangerous bacterial infection is a corneal infection due to Pseudomonas aeruginosa , which can permanently diminish visual acuity . Staphylococcus epidermidis, S. aureus and fungal organisms may also proliferate in contaminated mascaras . Infections are more common if the globe is traumatized by the infected mascara wand. Even though mascaras contain antibacterials, it is still wise to discard all mascara tubes after three months and not allow multiple persons to use the same mascara tube .

There are several mascara formulations that are less likely to support bacterial and fungal growth ( Table 153.7 ). Mascaras are available as water- or solvent-based and as a water/solvent hybrid. Water-based mascaras are easily removed with water and less likely to cause eye area irritation, but the presence of water provides a welcome medium for bacterial growth. Solvent-based mascaras are manufactured without water, must be removed with a special cleanser, and are more irritating; however, they are less likely to support bacterial growth and are therefore the formulation of choice for individuals who are carriers of Staphylococcus or Streptococcus spp . The water/solvent hybrid mascaras are an attempt to provide a water-resistant cosmetic with the benefits of both.

Another dermatologic side effect of the use of mascara is conjunctival pigmentation, resulting from the washing of mascara into the conjunctival sac by lacrimal fluid . This colored particulate matter can be observed on the upper margin of the tarsal conjunctiva. Histologically, the pigment is seen within macrophages and extracellularly in association with a variable lymphocytic infiltrate. Electron microscopy suggests that ferritin, carbon, and iron oxides are present within the tissues . Unfortunately, there is no treatment for the condition, which is usually asymptomatic.

Specialty mascaras are available for curling and elongating the eyelashes. These mascaras contain pigmented polymers that polymerize on the eyelash as they dry. The polymer then shrinks, curling the eyelash and placing a thin, long-wearing, pigmented film around the hair which thickens and elongates the lash. In addition, a prescription cosmeceutical containing bimatoprost 0.03% (Latisse ^® ; originally indicated for the treatment of glaucoma) is available to elongate eyelashes via prostaglandin modulation (see Ch. 129 ) . Side effects include iris and eyelid pigmentation, which may be permanent.

Lipsticks

Lipstick is a lip cosmetic designed to frame the teeth. Traditional lipsticks are mixtures of waxes, oils and pigments in various concentrations to yield the characteristics of the final product. For example, a lipstick designed to remain on the lips for a prolonged period of time is composed of high wax, low oil and high pigment concentrations, whereas a product designed for a smooth creamy feel on the lips is composed of low wax and high oil concentrations . The waxes commonly incorporated into lipstick formulations are white beeswax, candelilla wax, carnauba wax, ozokerite wax, lanolin wax, ceresin wax and other synthetic waxes. Usually, lipsticks contain a combination of these waxes carefully selected and blended to achieve the desired melting point. Oils for pigment dispersion are then selected, such as castor oil, white mineral oil, lanolin oil, hydrogenated vegetable oils or oleyl alcohol, to form a film suitable for application to the lips .

Newer lipstick formulations contain long-wearing polymers that create a waterproof film over the lips that remains in place indefinitely until worn away with speech or eating. These long-wearing lip products can cause cheilitis, due to their non-moisturizing formulations. In addition, lip products are marketed that claim to plump the lips. These products contain irritants, such as capsaicin, that create a mild irritant contact dermatitis resulting in short-lived lip edema.

Certain common lipstick ingredients can cause problems in the sensitized patient . Castor oil, found in almost all lipsticks due to its excellent ability to dissolve bromo acid dyes, can cause allergic contact dermatitis . Even the bromo acid dyes, such as eosin (D & C Red No. 21), found in indelible lipsticks can cause allergic contact dermatitis . Other lipstick ingredients reported to cause allergic contact dermatitis include: waxes (e.g. propolis ), preservatives (e.g. propyl gallate , benzoic acid ), sunscreens (e.g. oxybenzone , benzophenone-3 ), colors (e.g. lithol rubine BCA [Pigment Red 57-1] ), fragrances (e.g. peppermint oil), vitamin E, and ricinoleic acid .

Facial cosmetics for camouflaging

All of the colored cosmetics previously discussed are used in combination for facial camouflaging purposes in order to minimize facial defects while accentuating attractive facial features. Camouflage cosmetics are used by paramedical aestheticians, dermatologists, plastic surgeons, and cosmetic consultants . Their successful use requires a well-formulated, quality product applied with the skill of a stage make-up technician and the artistic abilities of a painter . Facial defects requiring camouflaging are defects of pigmentation and/or contour .

Pigmentation defects represent abnormalities limited to the color of the skin, whereas contour defects are defined as areas where the facial skin is hypertrophic or atrophic, with textural changes due to the absence of appendageal structures. Table 153.8 lists examples of pigmentary abnormalities frequently encountered by dermatologists that arise from inflammatory disorders, systemic diseases, or extrinsic effects (e.g. sun exposure). Pigmentation defects or discolorations can be camouflaged either by applying an opaque cosmetic that allows none of the abnormal underlying skin tones to be appreciated or by applying foundations of complementary colors. For example, red discoloration can be camouflaged by applying a green foundation, since green is the complementary color to red. The blending of the red skin with the green foundation yields a brown tone, which can be readily covered by a more conventional facial foundation. Furthermore, yellow skin tones can be blended with a complementary-colored purple foundation to also yield brown tones.

Table 153.8

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