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| Issue 24 |  |
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| Category | Title | Author | ||
| Guest Article | Baby Skin Care | Michaela Arens-Corell |
The good health and well-being of their baby is the most important objective of parents. Health-enhancing food, clothing, furniture and not least skin care products play a key role. If a baby care product is recommended by a competent party - other parents, physicians, the media or trade literature - and if it stands the test on application, a high brand loyality is to be expected, and the products are sometimes even recommended to other parents. On the other hand, consumers are very sensitive towards any risks presented by the products.
| Figure 1: Anatomic and functional features of baby skin | |
 Source:
Corel Draw Magic |
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Larger ratio of body surface to body volume than in adults |
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| Thinner skin than adults | |
| The horny layer has a higher moisture content and a looser structure than that of adults | |
| Lower sweat and sebum formation | |
| The acid mantle is built in the first few weeks and at first is more susceptible to disturbances than that of adults |
Thus, baby care product manufacturers are faced with the task of creating products with maximum caring properties and minimum risks in accordance with the current state of the art in skin research. There, the special characteristics of baby skin must be taken into consideration as follows.
Characteristics of baby skin
Due to the anatomic and physiological particularities of baby skin, baby care products must fulfill other criteria than skin care product for adults (1; 2; 3) (Figure 1).
Thin baby skin has a high water content in the horny layer and its barrier function, which is not yet completely developed, is particularly exposed to desiccation and external stimuli (4). Protection through sebum, as it is given in adult skin, is not yet very pronounced. After the transition from the protective environment of the womb to changing temperatures, with low ambient air humidity, mechanical pressure as well as the contact with germs, pathogens, harmful and irritating substances, baby skin slowly matures after birth.
| Figure 2: Influence of pH value on the configuration of horny layer lipids according to (7) | |
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Left: bilamellar, barrier effective structure |
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| Right top : micelle; right bottom: disordered structure |
Development and function of the acid mantle
In the beginning, newborn infants have an almost neutral skin surface with an average pH value of 6.5 (5). Metabolism processes in the horny layer, the secretion of sweat and small amounts of sebum and the beginning colonization of the skin with microorganisms ensure a gradual adjustment of an acid pH value of 5.5 (on average) on the skin surface during the first month of life. This acid mantle fulfills a series of major protective functions for the skin. According to recent findings, the synthesis of some horny layer lipids which function as a barrier from their precursors, e.g. the formation of ceramides through b-glucocerebrosidase and the acid sphingomyelinase, is dependent on the acid environment (6). In experiments, scientists observed an inhibition of the barrier regeneration after stripping with adhesive tape or treatment of the horny layer with acetone under the influence of a buffer with pH 7.4 by comparison with pH 5.5 (6). Furthermore, the acid environment in the horny layer stabilizes the double-lamellar structure of the intercellular lipids (7). PH values below 4.5 and above 6.0 destabilize the well-ordered structures and their functional ability as penetration barrier (Figure 2).
This explains the clinical observation of an increased desiccation of the skin by cleansing with neutral and alkaline surfactant preparations by comparison with weakly acid preparations (8) (Figure 3).
| Figure 3: Dependence of pH on desiccation of the skin after washing with syndets according to (8) | |
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Even the microbial colonization of the skin is controlled by the pH value of the skin (9). The "microflora" of the skin is developed by inoculation of microorganisms at skin contact with adults during the first weeks of life. A growth inhibition of pathogenic germs due to the weakly acid pH value, as is the case with adults (9), is not given in infants in the first month of life. The influence of the pH values of skin care preparations on the development of the resident microflora of baby skin has not been investigated so far.
The pH value of skin cleansing products may attack the acid mantle and disturb it for a long period of time. This was demonstrated for soap used by adults (10) and by small children (11) (Figure 4).
The change of the pH value correlates with an increased desiccation. Furthermore, soap-free surfactant preparations with a neutral pH value have a negative effect on the acid mantle of the skin (9). The pH value of the water phase of skin conditioning emulsions also has a long-lasting influence on the pH of the skin surface (Figure 5) and the hydrating effect (12).
Although these facts have been demonstrated in numerous scientific studies and despite the fact that skin care preparation with skin physiological pH values such as Sebamed have been on the market for over 30 years, only few manufacturers have considered the aspect of adjusting the pH value to the acid mantle in baby skin care products.
Skin cleansing in babies
When cleansing baby skin, there is normally no strongly adhering soil to remove. The desiccating and defatting effect and the irritation potential must be small, especially there should be no stinging in the eyes or mouth. Mild washing active substances such as sulfosuccinates, betaines and alkyl polyglycosides (13) (Figure 6) should find applications in baby care products.
| Figure 4: Changes in pH of baby skin 10 minutes after washing with soap and soap-free syndet preparations with pH 5.5 according to (11) | |
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| Figure 5: Changes of pH value after application of creams with various pH values in the water phase according to (12) | |
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Yet, there are still cleansing products which incorporate sodium lauryl sulfate. It is, however, not always advisable to apply refatting substances (14). Baby care formulas which are free from preservatives, fragrances and coloring agents convey an impression of higher compatibility. On the other hand, they have a negative effect on cosmetic properties and product stability. Substances used as substitutes for the preservatives listed in the EU cosmetics guidelines due to their antimicrobial properties, e.g. alcohol, cationic surfactants, or essential oils may also cause irritation or even allergies, no other than regular preservatives.
More detailed information about skin compatibility may only be obtained by careful product testing. The handling of skin care products has a strong influence on skin compatibility. In cases of dry skin and atopic eczema, daily baths are not recommended. Extensive baths for more than 15 minutes are not advisable at any rate. The water temperature should not be above 35° C. It is recommended to dose skin cleansing products sparingly. Overdosage often occurs when foam is considered as a measure for the cleansing effect.
| Figure 6: Mild washing active substances for cleansing of baby skin | |
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Example for an anionic
surfactant |
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| Example
for an amphoteric surfactant Cocoamido propyl betaine (INCI: Cocamidopropyl Betaine) |
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| Example
for a nonionic surfactant Decyl Polyglucose (sugar surfactant) (INCI: Decyl Polyglucose) |
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Skin cleansing in the diaper area
Skin cleansing in the diaper region has to be performed several times a day in order to remove excrement or urine residues completely. It is advisable to use wipes containing cleansing lotions or oil. From an ecological point of view, biologically degradable tissue material such as viscose is preferable. As far as cleansing lotions are concerned, the above mentioned considerations should be applied as well. In addition to cleansing the skin, oily wipes also have an conditioning effect but are less suited for other skin areas by comparison with wipes containing cleansing lotions. Once again, manufacturers should proof the skin tolerance by suitable compatibility tests.
Skin care and protection for babies
Due to fact that baby skin has a reduced barrier function and an increased tendency to dry out, putting on cream is a major part of the skin care routine. Basically, guidelines for skin care products should be conceived as defined in the Society for Dermopharmacy's guideline "Dermocosmetics for dry skin care" (15). In addition to oils, mostly water-in-oil or oil-in-water-emulsions are applied. Water-in-oil emulsions are best suited for the diaper area and skin regions which are exposed to all weather conditions. Oil-in-water emulsions are highly accepted for large-scale applications. Paraffin oil still is predominant in the oil phase of the products available on the market and is often combined with vaseline. Doubts about product compatibility and the risk for a total occlusion mediated by such mineral oils cannot be confirmed from the experience of dermatologists and pediatricians. A restricted occlusion against excrements and urine makes sense especially in the diaper area. Vegetable oils are increasingly incorporated in skin care products. Oils with high proportions of unsaturated fatty acids and, most recently ceramides, are regarded to have particularly good caring effects. Moisturizing substances such as glycerine (16), antioxidants such as tocopheryl acetate (17), antiinflammatory additives such as chamomile extract or bisabolol and therapeutic substances such as panthenol (18) have proven to be worthwhile in skin care preparations (Figure 7). Zinc oxide is mostly incorporated in diaper rash creams because of its antiinflammatory and antimicrobial properties.
| Figure 7: Examples of active agents in skin care products for babies | |
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Oily substances: Paraffin oil (INCI: Paraffinum liquidum), vaseline (INCI: Petrolatum), vegetable oils such as oil of sweet almonds (INCI: Prunus dulcis), unsaturated fatty acids such as linoleic acid (INCI: Linoleic Acid), ceramides as Ceramid 3 |
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| Humectants: Glycerine, sorbitol, hyaluronic acid | |
| Radical scavengers : Vitamin E acetate (INCI: Tocopherylacetat) | |
| Antiinflammatory substances : Chamomile extract (INCI: Chamomilla recutita), Bisabolol | |
| Therapeutic substances: Dexpanthenol (INCI: Panthenol) | |
| Covering substances: Zinc oxide (INCI: C.I. 77947), titanium dioxide (INCI: C.I. 77891) |
In view of the small number of detectable allergies to fragrances in skin care products for babies - according to IKW (German Cosmetics and Detergents Association) statistics there is an average total of one allergic reaction in reference to one million cosmetic packages sold (19). According to estimations by dermatologists one third is caused by fragrance substances. The application of fragrance substances in skin care products for babies is nevertheless justified because it improves the cosmetic acceptance of a product and enables the application of substances which may develop an disagreeable odor such as unsaturated fatty acids do. In the case of proven allergies against certain fragrance substances, however, perfume-free products are recommendable. The topic of preservatives has been discussed above. Coloring agents are only rarely applied in skin care products. Polyethylene glycoles (PEG) are a substance group which is also criticized from time to time, because PEG's are supposed to have a penetration promoting effect. However, the chemical variety of this substance group does not allow such a general conclusion. Compatibility tests performed on the finished products are a more reliable basis for evaluations.
As far as emulsions for skin care applications are concerned, the pH value has to be given credit as well. Because these preparations stay on the skin for a long time, their influence on the acid mantle is not to be neglected. It is desirable to maintain a weakly acid pH on the skin surface, especially with regard to the pH dependence on the synthesis of barrier lipids.
| Figure 8: Requirements for product documentation taken from the guideline for dry skin care according to (15) | |
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Information required to evaluate the quality of a dermocosmetical product for dry skin care should be documented by the manufacturer or marketer of products and made accessible to experts. This documentation should at least include information on the following items: |
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| Description of the galenic system | |
| Information on shelf life and microbiological stability | |
| Efficacy proofs for the effects claimed for dry skin care by means of a comprehensive representation, e.g. informative figures and tables by quoting the source | |
| Summary of results of the compatibility tests carried out by stating the testing authority |
In order to make it easier for experts to give competent advice on baby care products, manufacturers could provide physicians and pharmacists with detailed information about their products - surpassing the simple stating of ingredients as demanded by law. Relevant information is summarized in the already mentioned guideline "Dermocosmetics for dry skin care" by the Society for Dermopharmacy (14) (Figure 8). In the selection of suitable skin care products for their baby, many parents will benefit from sampling and a product information service made accessible by the manufacturers.
References
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1
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Niedner, R., Ziegenmeyer, J., Dermatika. Wiss. Verlagsges. mbH Stuttgart 1994 |
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2
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Ramasastry, P.; Downing, D.T.; Pochi, P.E.; Strauss, J.S., Chemical composition of human skin surface lipids from birth to puberty. J. Invest. Dermatol. 54, 139-144, 1970 |
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3
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Solomon, L.M.; Esterly, N.B., Neonatal dermatology. The new born skin. J. Pediatr. 77, 888-894, 1970 |
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4
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Caputo, R.; Monti, M., Children's skin and cleansing agents. Wiener Med. Wochenschrift, Suppl. 108, 24-25, 1990 |
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5
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Beare, J.M.; Cheeseman, E.A.; Gailey, A.A.H.; Neill, D.M.; Merrett, J.D.: The effect of age on the pH of the skin surface in the first week of life. Br. J. of Dermatol. 72, 62-66, 1960 |
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6
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Mauro, Th.; Holleran, W.M.; Grayson, S.; Gao, W.N.; Man, M.Q.; Kriehuber, E.; Behne, M., Feingold, K.R.; Elias, P.M. Barrier recovery is impeded at neutral pH, independent of ionic effects: Implications for extracellular lipid processing. Arch. Dermatol. Res. 290, 215-22, 1998 |
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7
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Osborne, W.; Friberg, S.E., Role of stratum corneum lipids as moisture retaining agents. J. Dispers. Science Technol. 8, 173-179, 1987 |
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8
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Gehring, W.; Geier, J.; Gloor, M., Untersuchungen über die austrocknende Wirkung verschiedener Tenside. Dermatol. Monatsschrift 177, 257-264, 1991 |
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9
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Schmid, M.-H.; Korting, H.-C., The concept of the acid mantle of the skin: Its relevance for the choice of skin cleansers. Dermatology 191, 276-280, 1995 |
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10
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Korting , H.-C.; Braun-Falco, O., The effect of detergents on skin pH and its consequences. Clinics in Dermatology 14, 23-27, 1996 |
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11
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Gfatter, R.; Hackl, P.; Braun, F., Effects of soap and detergents on skin surface pH, Stratum corneum hydration and fat content in infants. Dermatology 195, 258-262, 1997 |
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12
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Gehring, W., Emulsionen heben die Feuchtigkeit der Hornschicht stets deutlich an. Interne Klinikzeitung der Alexanderhausklinik Davos, 3, 18-19, 1999 |
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13
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Kresken, J.: Maßnahmen zur Verhütung berufsbedingter Hauterkrankungen. Dicke, W., Mehlem, P. (Hrsg.), Alles über Hautschutz, Hautreinigung, Hautpflege, 3. Aufl., 51-69, Wirtschaftsverlag NW, Bremerhaven (1993) |
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14
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Gehring, W.; Fischer, M.; Gottfreund, J.; Gloor, M., Effect of various additives on the skin tolerability of a wash solution. Dermatosen 44 (4), 160-163, 1996 |
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15
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Leitlinie der GD Gesellschaft für Dermopharmazie e.V. Dermokosmetika für die Pflege der trockenen Haut. Gesellschaft für Dermopharmazie 1999 http://www.gd-online.de/leitlinienkosmetik.htm |
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16
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Gloor, M.; Schermer, S.; Gehring, W.: Ist eine Kombination von Harnstoff und Glycerin in Externa sinnvoll? Z. Hautkr. 72, 509-514, 1997 |
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17
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Gehring, W.; Fluhr, J.; Gloor, M.: Influence of vitamin E acetate on stratum corneum hydration. Arzneim.-Forsch./Drug Res. 48, 772-775, 1998 |
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18
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Eggensperger, H., Multiaktive Wirkstoffe für Kosmetika. SÖFW-Journal 120, 178-182, 1994 |
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19
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Raab, W.; Kindl, U., Pflegekosmetik. 3. Aufl. Wiss. Verlagsges.mbH, Stuttgart 1999 |
Author
Dr. Michaela Arens-Corell
Dr. rer. nat. Michaela Arens-Corell, with Sebapharma GmbH & Co. KG since 1992, studied Biology and received a doctorate there. After research in the pharmaceutical industry she became active in skin care and is now head of Sebapharmas' Medical-scientific Department. As far as the Sebamed products are concerned, her findings of skin research there yield into product development, marketing, public relations and consumer care.
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