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Guidelines "Dermocosmetics for the Cleansing of Dry Skin" (version of 22 January 2001)
The general purpose of skin cleansing is to remove soiling, excessive skin parts (skin scales, sweat, sebum), unwanted micro organisms and their metabolic products as well as possibly existing residues of medicinal or cosmetical preparations from the skin surface. A product recommendation should only be given if certain quality standards are ensured, i.e. if galenic properties, wanted and unwanted effects are sufficiently investigated and documented. So far a standardized, interdisciplinarily harmonized concept has not been established. This is why the department Dermocosmetics of the GD Gesellschaft für Dermopharmazie e.V. (Society for Dermopharmacy) as independent organization undertakes to lay down minimal requirements regarding quality and documentation in the form of the present guidelines. These guidelines are intended to be a support for all those who are concerned with dermocosmetics for the cleansing of dry skin.
They are a systematically elaborated recommendation offering the target group an orientation when making decisions about adequate measures for the cleansing of dry skin and have been established by an interdisciplinary expert group by evaluating relevant international literature.
They apply to "standard situations" taking into consideration the current scientific findings available for the corresponding questions. These guidelines require permanent revision and if necessary modifications founded on scientific findings and the feasibility in daily practice. Consideration of the guidelines does not ensure in every case the achieving of the objective strived for. It does not lay claim for completeness.
The term "Dermocosmetics" designates measures for the care, protection and cleansing of skin for which the application purpose is achieved under co-consideration of dermatological and pharmaceutical aspects. Cosmetical products coming up to these demands are defined as "Dermocosmetics".
Dermocosmetics for the Cleansing of Dry Skin
Dermocosmetics for the cleansing of dry skin are such products for which their intended purpose "for dry skin" or "application for dry skin" is indicated.
They are to feature a good skin tolerability at a satisfactory cleansing effect and an application frequency as usual for the product type. An existing dryness of skin should not be intensified by a regular application.
As all cosmetical products, dermocosmetics for the cleansing of dry skin are also subject to the Cosmetics-guidelines of the European Community. Legal basis in the Federal Republic of Germany is the Lebensmittel- und Bedarfsgegenständegesetz (Food and Consumer Good Act) in combination with the Cosmetics-decree, in Austria the Lebensmittelgesetz (Food Act) in combination with the Cosmetics-decree and in Switzerland the Lebensmittel- und Gebrauchsgegenstände-Gesetz (Food and Consumer Durables Act) with the decree about cosmetic preparations in the respectively valid versions.
Target group of these guidelines are persons developing, preparing, testing, analysing, commericializing, giving advice as to their application, selling as well as consumers.
These guidelines are a systematically elaborated representation and recommendation. They describe quality standards relating to preparations and offer support in the decision for measures as to the cleansing of dry skin to the persons indicated above.
The term dry skin (xerosis, xerodermia) describes a skin condition which is characterized by a reduced quantity and/or quality of humidity and/or lipids. Objectively the appearance of dry skin is marked by roughness, scales, dullness and/or a lack of elasticity. Subjectively a sensation of tension and itching may appear with dry skin. These subjective symptoms can also manifest isolatedly.
Dry skin in the sense of these guidelines is to be understood as a symptom and not an isolated clinically defined dermatosis as for instance dermatitis, psoriasis or ichthyosis. Dry skin reacts more intensely than normal not dry skin to external chemical and physical noxae.
According to expert opinions dry skin appears very frequently; only in Germany several million persons are affected. Epidemiological data are not available.
The exact aetiopathogenesis of dry skin is still open. Persons being inclined to atopy have a defect of the barrier function of the horny layer of the epidermis which can result in a transepidermal waterloss. Mainly the horny layer lipids (1-3) are lacking. Dry skin can however also be caused by a sebostasis (reduced sebaceous gland activitiy) (4). Equally a reduced water binding capacity can be the case.
Causes and development:
Dry skin is either genetically conditioned or acquired. It appears as a symptom of a skin disease, e.g. of the atopical dermatitis (5), an internal disease, e.g. a pyeolopathy (6) or the diabetes mellitus (7). Dry skin can also be caused by exterior influences, as for instance by having showers too frequently and intensively or taking baths with or without using soaps or syndets (8 - 11). In addition, occupational strains, e.g. when exercising "humid professions" (hairdressers, etc.) as well as occupations in the construction and metall processing trade (12) may cause the emergence of dry skin. This equally applies to climatic factors as cold or low atmospheric humidity (13).
Statements of persons concerned lead to the diagnosis of dry skin and in addition a visual and palpatoric examination. Apparative diagnostical methods are among others: measurements of skin roughness (5, 14, 15), moisture content (16-18), determination of the transepidermal waterloss (19, 20), fat content (1) and scale formation (22) as well as the measurement of skin glossiness (23).
The properties of dermocosmetics for the cleansing of dry skin are attached to the overall formulation.
findings allow in principle different formulation types for the cleansing of dry
skin which are attributed to the washing, having showers or baths. In this context
preparations on surfactant basis prevail (soaps in the form of bars or liquids
and syndet preparations, the latter are for example designated as washing emulsion,
washing lotion, washing gel, shower bath, foam bath). These products partly contain
additional lipid components for the purpose of fat restoring in skin. They are
for instance indicated as shower creams or oils or hand washing creams or oils.
Oil baths for the cosmetical application are available containing emulsifiers
(emulsion baths) and as emulsifier-free preparations (spreading baths). The latter
are predominantly applied for the purpose of skin care. For the facial use there
are equally cleansing agents containing emulsifiers (e.g. cleansing milks) and
emulsifier-free cleansing agents (e.g. facial cleansing oils) available. For special
purposes (e.g. in peeling preparations and hand washing pastes) cleansing agents
contain additionally rubbing agents. Besides for the cleansing of the face, body
and hands, cleansing tissues on the basis of oils, emulsifiers, surfactants and/or
solvents are obtainable.
The attribution of a skin cleansing effect only requires a separate proof if the preparation serves a special purpose, e.g. facial cleansing preparations for the removal of decorative cosmetics. In the commercial field these are hand cleansing preparations for the removal of heavy soilings by waste oil, varnish, adhesives, etc.
For an assessment of the cleansing effect of individual preparations standardized wash tests simulating the washing process can be performed (24-26). Basis of the effectiveness proof is on the one hand a comparison with skin areas which are only cleaned with water and on the other hand a comparison with the starting value, i.e. the value before the washing process (intra-individual comparison).
An additional benefit for the cleansing may among others lie in an increase of the fat or moisture content, a maintaining or amelioration of the barrier function or a skin smoothing. For the evidence of such effects, the methods indicated for diagnostics are applicable (refer to chapter "Definition of dry Skin"). These measuring methods are apt as far as they supply relevant, reproducible and valid results and correspond to the respective status of scientific findings.
For a proof of the cleansing effect as well as for the detection of additional care effects the respective study design has to be chosen in a way that the number of probationers for the selection of adequate statistical methods is sufficiently high so that differences can be registered. For details of the study design a reference is given to the relevant expert literature (27, 28).
Application risks of dermocosmetical preparations for dry skin can be intolerability reactions as acute or chronical-cumulative irritative contact dermatitis, sensoric irritations or allergic contact dermatitis on the basis of a sensitization of the delayed reaction type as for other preparations for topical application. Among these risks for skin cleansing agents the chronic-cumulative irritative contact dermatites are the most frequent skin diseases in this field (29). In this connection besides the composition also the dosage of the cleansing preparations is important as well as frequency and duration of the washing process and in addition the water temperature, the pH-value and the hardness of water (30-32).
For testing and assessment of the skin tolerability appropriate in-vivo and in-vitro methods can be applied (27, 33-37). Basis for these tests should be the Notes of Guidance for the examination of the safety of cosmetic preparations annex 11 and 12 of the SCCNFP (8). The rest reactions can be objectified by means of non-invasive skin physiological methods (39). In combination and as complement, standardized washing and controlled application tests (practical tests) can be performed (24-27, 35).
As method for the risk assessment of an acute irritation the occlusive, epicutaneous patch test is recommended (27, 35).
The chronical-cumulative irritation can be counted by means of the cumulative epicutaneous patch test (40), the Duhring-chamber-test (1), the bend of elbow washing test (42) as well as the forearm washing test (43).
For examining of the sensoric irritation there are procedures making use of the releasing of a comparable stabbing sensation by organic acids, e.g. sorbic acid or lactic acid (44).
For the recording of the sensitization potential of dermocosmetics for the cleansing of dry skin at present no validated and ethically generally accepted methods are available. Alternatively it is recommended to make a thorough selection of raw materials and to avoid the use of for example known allergens with a comparably high sensitization potential (for example ) known from relevant publications.
For the tolerability proofs the information regarding the study design given in chapter "Wanted Effects and Tolerability Proofs" is also to be adhered to.
Information necessary for the quality assessment of dermocosmetics for the dry skin cleansing is to be documented and made accessible to the experts by the manufacturer respectively seller of the preparation.
should at least contain information as to the following subjects:
(2) Di Nardo A., Wertz P., Gianetti H. et al.: Ceramide and cholesterol composition of the skin of patients with atopic dermatitis. Acta Derm. Venereol. 78, 27-30, 1998
(3) Melnik B., Hollmann J., Plewig G.: Decreased stratum corneum ceramides in atopic dermatitis individuals - a pathobiochemical factor in xerosis? Br. J. Dermatol. 119, 547-549, 1988
(4) Proksch E.: Die Permeabilitätsbarriere der Epidermis und ihre Beeinflussung durch Detergentien und Lokaltherapeutika. Ärztl. Kosmetol. 19, 424-434, 1989
(5) Linde Y.W., Bengston A., Loden M.: Dry skin in atopic
dermatitis. A surface profilometry study. Acta Derm. Venereol. 69, 315-319, 1989
(7) Yosipovitch G., Hodak E., Vardi P. et al.: The prevalence of cutaneous manifestations in IDDM patients and their association with diabetes risk factors and microvascular complications. Diabetes Care 21, 506-509, 1998
(8) Gammel C.E., Pagnoni A., Kligman A.M., el Gammal S.: A model to assess the efficacy of moisturizers - the quantification of soap-induced xerosis by image analysis of adhesive coated discs. Clin. Exp. Dermatol. 21, 338-343, 1996
(9) Gfatter R., Hackl P., Braun F.: Effects of soap and detergents on skin surface pH, stratum corneum hydration and fat contents in infants. Dermatology 195, 258-262, 1997
(10) van der Falk P.G., Cryns
M.C., Nater J.P.: Skin irritancy of commercially available soap and detergent
bars as measured by water vapour loss. Clin. Exper. Dermatol. 10, 98-103, 1984
H., Wiebusch M., Heinrich U., Stute R: Zur Bewertung der Oberflächenstruktur der
Haut (SELS) Akt. Dermatol.23, 290 -295, 1997
The guidelines have been established on behalf of the GD Gesellschaft für Dermo-pharmazie e.V. (Society for Dermopharmacy) by the a.m. expert group as consensus paper.
for publication: 22 January 2001
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