What is suggested
Definition of dry skin
Dry skin, also called xerosis, is one of the major clinical components of atopy. It can notably be characterized by clinical, biochemical, biometrological, and histological or immunological properties.
Dr Christian Moussard |
Clinically, the skin is rough and irregular, except in the areas with a high level of sebum. It is often accompanied by functional signs of variable intensity (pruritus, sensation of tautness).
Dry skin can be observed, besides atopy, in numerous pathological (deficient syndromes, renal failure) or environmental (winter, lowered humidity, air conditioning) situations.
In the case of newborns, dry skin is always considered as being pathological. It could be the only outward sign of atopy.
What we know
The biochemical aspects of dry skin
The protection against the body’s water depletion is an important function of the epidermis and the cornean layer. The lipidic structure of the intercellular matrix of the cornean layer, to which participate on the first level the ceramides, have a leading role for creating this barrier function.
For atopic dermatitis where the complex physiopathology associates genetic predispositions and environmental factors, perturbations of this lipidic structure, mainly a reduction of the ceramides rates and of long chain fatty acids seem to account for functional anomalies observed in dry skin, in particular a changement of the barrier function followed by the increase of transepidermic water deperdition, a skin dryness and favours penetration of harmful agents.
It has been demonstrated, among others, that the increase of activity of sphingomyeline desacylase diverts these substrates from transformation into ceramides, followed by a deficit in ceramides.
It is, however, evident that the barrier function of the cornean layer does not depend on an unique lipidic composant but on its whole architecture, including lipids and proteins
From left to right, from the front: : |
Recent theory on atopy, the hygienist theory
Epidemiological data on atopic dermatitis have shown a significant increase in the number of cases in the last 20 years, reaching between 15 and 20% in western countries. This increase can be explained by all the protective or hygiene measures aiming at limiting infection, particularly during the first months of a child. This seems to apply to bacterial infections, indirectly brought to the fore by the presence of endotoxins (and in creches), viral infections (measles) or parasitic infections (Helminthiases, Shistosomiases).
The role of these infections in the prevention of atopic dermatitis is absolutely unknown at present. Several hypotheses implied in this disorder have nevertheless been put forward: antigenic competition, blocking of specific IgE, action on TH1 / TH2 balance or the role of IL10. Results of two studies of atopic dermatitis were given. The first study showed a preventive and even curative action of probiotic-based treatment during atopic dermatitis in newborn patients whilst the other study revealed the curative action of a non-pathogenic mycobacteria injection in men.
The therapeutic consequences are certainly important. We can easily imagine the effects of newly induced infections to prevent the appearance of autoimmune or allergic diseases, notably of atopy. Use of lyophilisats of bacterial extracts, inactivated agents or even of vaccines goes in this direction. Therapeutic studies are in progress. In the dermatological field, it is above all atopic dermatitis, which could benefit from this type of treatment although we could imagine it for other inflammatory and immunological cutaneous diseases such as alopecias areata, lupus, and sclerodermia…
What is measured
Biometrological methods that characterize dry skin
Bio-metrological instrumentation enables to characterize dry skin in the case of atopy. Three methods appear to be essential, each evaluating different parameters.
- 1/ Sampling of squama after application of an adhesive disc (D-Squame ®; Corneofix ®). Reading of the sample is performed in comparison with graphs or by means of imageanalysis. These discs made of supple and transparent polyester are covered with a transparent adhesive. They are easy to use and interpretation of the results is immediate.
- 2/ Quantitative measure of the hydration rate at stratum corneum level using a high frequency capacitance measure. This is known as the corneometer technique based on capacitance. The dielectric constant of the water present within the stratum corneum enables measurement of the variations caused by either an increase or a decrease of the water quantity. Measures of variations are performed according to condenser capacities. The probe includes two lamellar electrodes. With this method, it is the water content of the stratum corneum and the upper layers of the epidermis that is measured. The results are expressed in arbitrary units ranging from 0 to 120, from very dry to hydrated skin.
This device is especially used within the framework of clinical trials, or to obtain comparative values, before and after rehydration treatment. Atopic skin is characterized by a water content at stratum corneum level that is lower than average.
- 3/ Measure of the Trans Epidermal Water Loss: The barrier function of dry atopic skin is weakened and thus comes with an increase of the Trans Epidermal Water Loss (TEWL). This measure is a good way to quantify the alteration of the cutaneous barrier. Two devices are today available: the Évaporimètre EP (Servomed ®) and the Tewameters TM 210®.
These devices use the principle of the gradient of the water vapor measurement established at a 10 mm distance from skin surface. In order to carry out these measurements, particular environmental conditions with controlled temperature and relative humidity of the order of 40 to 50% have to be met.
"These 3 instrumental systems are in our opinion sufficient to characterize dry skin in atopy."
An educational reliable relation |
What should be done
Hygiene measures for atopic subjects
- Avoid putting your skin in contact with wool or synthetic fibers (the latter being less irritating). Choose clothes made of cotton only.
- Avoid using soaps or detergents. A dermatological cleaning bar is a perfect substitute.
- Whenever possible, try to avoid contact with water, or at least make it less frequent and prolonged. Cold water is less harmful than hot water (bathing in swimming pools is allowed provided you have a shower afterwards and apply an emollient as soon as you get back home). Seawater is practically harmless.
- Apply frequently emollients.
These specific precautions generally help to prevent the appearance of atopic dermatitis or to reduce it. Their aim being to promote a healthy, eczema-free skin. However, if eczema persists, do not hesitate to seek the advice of a specialist who will prescribe dermatological treatment.
Why the atopic subjects
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“Atopic subjects often present dry skin conditions. This is mainly due to a decrease in sebaceous secretion, a disorder in sudoral excretion (particularly blocked pores) and a lack of suppleness in the horny layer. As a consequence, feelings of discomfort are experienced by patients and can be triggered by cold, Moreover, the skin of atopic subjects is abnormally irritable as a result of a reduction in the pruriginous threshold. This irritation is generally what causes the eczema, hence the name Besnier prurigo often given to atopic dermatitis. Irritation can be caused by external and environnemental factors (too dry integument, woolen underwear, working among straw or dust, use of detergents) or by an internal stimulation of the immunity.”” P.Agache |
The patient’s education. Which training method for health professionals ?
The aim of therapeutic education is to improve management of patients suffering from chronic disorders through assistance that enables the patient to gain autonomy, develop new skills and finally learn to organize everyday life around the disease in the best possible way. The concept of therapeutic education, which can be found in the W.H.O’s recommendations, is today emerging in the French legislation with the law dating of 4/03/ 2002 and the rights of patients for the quality of health systems.
In the case of atopic dermatitis, therapeutic failure is above all connected to a bad compliance of the prescribed treatment and finally, the cortico-phobia, which is at the origin of most compliance problems. Therapeutic education thus represents a major indication in atopic dermatitis. This was also expressed by the families following treatment failures.
Therapeutic education
Therapeutic education is based on dialogue as well as the elaboration of a common project taking into account both the knowledge and doctor-patient expectations.
This kind of project generally includes the following three stages:
- Implementation of an educational trusting relationship, which corresponds to the educational diagnosis.
- The common definition of learning objectives; this is called the educational contract.
- And finally, and this is the third stage, the application, evaluation and permanent review of this contract.
- 1/ The educational diagnosis is the analysis of the patient’s experience with regard to his/her disease, - what is he suffering from?what does he do?, what does he know about the disease? What he believes, how he feels, what he wishes for … these are examples of questions that can improve diagnosis.
- 2/ The educational diagnosis aims at having the patient become autonomous on various points. Some examples: :
In practice, 4 questions are included in this face-to-face interview
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- “What can you tell me about your disease ?” This tells the doctor which speech to adopt and which information to give. - “What do you think of the treatments already prescribed ?”, or even “how does the patient relate with the taken medication, particularly in the case topical steroid therapy ?” - “How do you get on with your disease ?”this is the notion of acceptance or denial. - And finally “what do you expect from this interview ?” this shows the motivation. |
- Being capable of adapting his/her treatment to his/her cutaneous condition.
- Which treatment should be opted for and when should it be used?
- Being able to manage the pain caused by the disease.
- Being capable of taking the treatment without the help of others. This represents a very frequent and important objective for children over the age of 4, whose active participation can be obtained. The fact that the child is able to apply or take the treatment on his/her own reduces the risk of having a family crisis, particularly damageable for the mother-child relationship, or even for the relationship with brothers and sisters.
Educational tools are necessary and will be adapted to the educational diagnosis. For example, the follow-up booklet and the patient-doctor contract will help make the child feel more responsible about the treatment and is a good way to promote exchange during the next consultations
- 3/ Evaluation is indispensable. It is based on pre-defined criteria which include objective elements (SCORAD) but also scales to measure subjective factors.
Attending an atopy school is another nonexclusive answer to therapeutic education. Indeed, the information given to parents or the team of doctors and nurses, the collaboration between private and hospital doctors, the sharing of experience or resources and principally, the harmonization of practices, are essential elements that need to be promoted to extend this therapeutic education on a greater scale.
In the long run, objectives should integrate the multiplication of reference centers in France, based on teams of dermatologists and motivated trained health professionals, as part of the same thematic group of the French Society of Dermatology.
However, in a nearer future, therapeutic education must be entirely integrated and recognized as such in the management of severe atopic dermatitis in children and adults.
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| Dr Annick Pons-Guiraud |
Taking into account aggravating environmental factors
1 - Contact sensitization
Modification of the epidermal barrier leads to hyper-permeability of the skin, which favors the penetration of allergens and thus the development of contact dermatitis (CD).
About 40% of the patients suffering fromatopic dermatitis (AD) have become sensitive to contact allergens found in topical medication, cosmetics or air-brought allergens. Whatever the age of the atopic patient during consultation, especially in the case of moderate or severe dermatitis, it is necessary to look for these environmental aggravating factors. Although the interpretation and the accuracy of these tests are very delicate, it is important to systematically look for the allergen, which is responsible for pathology worsening.
The main allergens are perfume molecules, fragrances, some excipients and metals (the nickel for example).
- 1/ It is thus recommended, in the case of an atopic skin, which tends to become easily sensitized, not to use topical medicines or cosmetic products based on perfume molecules, the highly sensitiving preservatives and excipients, even from an early age and in the case of damaged skin.
- 2/ It is important to choose topical moisturizing care whose concentration in hygroscopicsubstance is not too high so as not to irritatethe integument and thus prevent sensitization to other molecules.
- 3/ Furthermore, do not forget that an atopic patient can always develop sensitization. Negative results from previous epidermo-tests are not definite since the frequency of product reformulations increases the risk of sensitization. This is why it is important to frequently re-control those results or take additional tests.
- 4/ Finally, it is imperative, before launching a product for atopic skin, to perform what we call»targeted» predictive tests, that is to say, on patients suffering from non-evolutional atopic dermatitis and on a healthy skin. This allergy check up will be carried out using either the active principle if the molecule is new or the finished product in the case of a modification of a previously marketed formula.
2 - Nutritional aspects in the prevention of AD
What can we reasonably advise in terms of food and primary prevention? Recent recommendations suggest applying food diversification after the age of 6 months for all infants regardless of their family history.
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Prolonged breast-feeding is recommended although the atopic mother needs to be informed on the risk of sensitizing her baby.
Moreover, food with a strong allergenic potential such a eggs, fish or kiwi, should not be given before 1 year old if the child shows signs of developing severe atopy. Peanuts or nuts in general will only be given after 4 or 5 years old.
(Table 1 and 2)
3 - Taking into account the baby and his family
It is important to understand the relation between the newborn (0 - 18 months) and his/her environment if we try to improve cutaneous pathology, often multi- factorial. Once protected in the closed universe of the uterine world, the newborn is suddenly surrounded by a world of stimuli, which can be excessive (too many solicitations or too stimulating and ill- adapted environment: light, noise, cold, heat). Here, the mother’s role is essential since she has to screen and filter those excessive stimulations for her baby and play a role of "barrier" without letting herself become too overwhelmed.
The father’s role completes that of the mother; he establishes or restores balance, plays the role of regulator and protects the mother-child relationship.
Avoid having a cat in the house. If the cat was already here, you can keep it as long as it does not affect the child (no symptoms upon contact) |
Having both the father and mother protect the child against excessive stimuli does not mean that stimulations should be banned, since they are a god way of guaranteeing harmonious development for the baby (cutaneous exchanges, cuddling, physical closeness, answers adapted to his/her needs, at the right time).
Every child reacts very differently to stimulation, which is why detailed knowledge of his specific functioning is always recommended.
The father’s role |
As a consequence, in order to achieve harmonious relation between the child and his/her body and environment, the parents have to understand their child’s personality in order to adjust to it and thus better respond to internal (hunger, discomfort, need of sleep) and external stimuli (mainly coming from the outside and the people who look after him/her).
It is also essential to know about the family context, the relations between the child and his/her environment, if the parents get along or other important family events.
Recent recommendations |
Thus, the psychologist’s job, as part of a multi-disciplinary team, consists in providing support, psychological assistance to families, clearly list the child’s features to facilitate adaptation with the environment, favor better treatment compliance and favorably modify the father-mother-baby relationship. Experience has shown that adaptation to the baby and the taking into account of the father-mother-baby relationship is systematically beneficial for the global therapeutic management.
What we already know
Reminder on the exact definition of primary, secondary and tertiary prevention |
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It is necessary to differentiate the measures taken for primary prevention, which aim at decreasing occurrence of the disease in a population by decreasing the risk of having new cases; those for secondary prevention, which try to reduce the prevalence of the disease in a population by decreasing its evolution and duration and finally the measures for tertiary prevention, whose objective is to limit prevalence of chronic disabilities by reducing to the minimum functional disabilities caused by the disease. Primary prevention of allergic symptoms in the case of atopic dermatitis is at present difficult. This is certainly associated to recent data concerning environmental factors and a “clean” lifestyle, which increase risk of allergy occurrence. Secondary prevention is hence probably needed. Could specific immunotherapy be here considered as a principal means of action? Tertiary prevention has become indisputable. A single element gathers the various aspects of prevention: smoking, which affects the development of respiratory tracts and most probably favors sensitization to allergens. |
Use of adapted pharmacological agents and galenic forms
Whether in the case of healthy or pathological skin, the galenic form applied to the skin will automatically have a specific effect on the integument’s structure. In these conditions, the objective of the lab assistant will be to develop galenic forms which are adapted to every “principal type” of pathology in order to optimize release of the active ingredient but also to produce a clear effect on the skin.
The formulation of a dermatological product for atopic dry skin, whether for therapeutic (development of medication) or cosmetic purposes will be based on these same principles.
The latter will have to integrate, besides the physicochemical characteristics (solubility, stability, concentration) of the active ingredient, the biologic elements, which define atopic dry skin. If we want to protect or even repair this particularly sensitive skin type, we first need to know its exact structure and reactivity so that we could start by making sure no high-risk product is used.
The galenic form in itself can be of any type since formulation will depend on final objectives. If emulsified forms are preferred, the surfactant that will be selected will have to respect the natural integrity of the horny layer. If we consider mimicry to biologic structures, lamellar presentations seem to have a promising future as they have in principle particularly interesting abilities to deliver the active ingredient and restore the surface lipidic film and inter-corneocytar lipids which are extremely deficient in atopic subjects.
