EMBRYOGENESIS OF THE SKIN
Embryonic period corresponds to the age of conception until two months of estimated gestational age (EGA). Fetal period refers to the age between second month of EGA until birth. Initiation of histogenesis of all skin regions and differentiation of some of those tissues occur during embryonic period. Formation and differentiation of tissues is continuous through all the trimesters. This section describes the formation and development of skin during various phases of fetal development (Table 1.1).
During the third week after fertilization, embryo undergoes gastrulation, resulting in the formation of ectoderm, endoderm and mesoderm. Shortly ectoderm divides into neuroectoderm and presumptive epidermis. At 30 days EGA, formation of skin is evident. By about six weeks the epidermis, dermo-epidermal junction (DEJ) and dermis are well delineated with nerve and blood vessel formation. Distinction between dermis and subcutaneous tissue is seen only at places. There is no evidence of formation of appendages.
The epidermis consists of simple, flat two-layered epithelium consisting of basal and periderm cells. Both layers are filled with glycogen. Both types of cells consist of a central nucleus with sparse cytoplasmic organelles around the nucleus or at the periphery of the cell. Keratin (K) intermediate filaments K19 and K8 are present in both, while K5 and K14 are expressed by basal layers. K18, a marker for Merkel cell, is also expressed by the cells of periderm. The filaments are dispersed in the cytoplasm or assembled in small, short bundles in association with desmosomes and hemidesmosomes. Basal cells express platelet-derived growth factor. Microvilli project from the peridermal surface into the amniotic fluid. Although melanocytes are found to be dendritic by about 50 days, there is lack of evidence of melanosomes in the cytoplasm. Langerhans’ cells are recognized as early as 42 days EGA based on the presence of ATPase, HLA-DR and by their truncated or dendritic morphology. They are probably derived from the yolk sac or fetal liver with a density of about 50 cells/mm3.
Merkel cells can be recognized by 55–60 days using keratins K8, K18, K10 and K20. They are neuroendocrine cells distributed at a density of 130 cells/mm2. Merkel cells are derived from keratinocytes in situ.
The molecules and antigens characteristic of basal laminae (type IV collagen, laminin, heparan sulfate proteoglycan, nidogen/entactin) are expressed by 8 weeks. Skin-specific molecules are recognized during late first trimester. The antigens associated with the attachment structures are not recognized by light microscopy although keratinocytes have begun synthesizing them.
The dermis is highly cellular, but also contains extra cellular fibrous matrix proteins and type I, III, V and VI interstitial collagens. It consists of mesenchymal cells which are stellate and rich in glycogen. It also contains hyaluronic acid-rich proteoglycan matrix. Compact mesenchyme with a zone of sulfated proteoglycans, situated beneath the epidermis is rich in growth factors and receptors.
Elastic fibers are not detectable by light microscopy, although fibrillin and elastin can be recognized immuno-histochemically and microfibrils by electron microscopy. Fine nerve fibers, arterioles; venules and capillaries are present within compact mesenchyme and deep dermis. The large nerve trunks and vessels are located in subcutaneous tissue.
Type IV collagen is present in basement membranes around the vessels, while type III and V collagen in vascular sheets. Autonomic nerves are not recognized.
The skin has a mucoid quality and is prone to errors in development at this stage. Transition from embryo to fetus also heralds the formation of appendages (discussed later). The hallmark of this stage is stratification of epidermis with an additional intermediate layer. Intermediate layer expresses K5 and K14 similar to basal layer. Additionally K1 and K10 are also present. Other markers of keratinocyte differentiation like pemphigus antigen, cornified cell envelope proteins; blood group antigens and cell surface glycoproteins are also expressed. This layer also contains glycogen. Genetic diseases involving mutation of keratins can be recognized by this period. At the same time cells of the periderm increase in size and develop microvilli-covered blebs.
Around 80 days EGA, melanocytes are present in maximal density (3000/mm2). The number decreases towards birth. Melanosomes in these cells can be recognized by late first trimester. The knowledge about this helps in the prenatal diagnosis of tyrosinase-negative oculocutaneous albinism.
By about 80 days, Langerhans’ cells are highly dendritic, begin to express CD1a at the surface and develop Birbeck granules.
Merkel cells are located along the primary epidermal ridges of palmar skin and at a maximum density of 1400 cells/mm2. They are found in association with developing hair follicles and sweat glands. They are also present in the dermis and are thought to originate from follicular or interfollicular epidermis. They may play a role in the organization of nerve fibers. Dense Core granules, characteristic marker for Merkel cells are absent.
DEJ has acquired adult features with well-developed hemidesmosomes, anchoring filaments and fibrils. Dermal and subcutaneous mesenchymal cells assume fibroblastic morphology and synthesize matrix molecules. Papillary and reticular dermis is demarcated based on increased cell density proximal to the epidermis, and larger collagen fibril diameter and fiber bundle size in reticular dermis. Adult vasculature is developed with one plexus at dermo-subcutaneous boundary and the other at the boundary between the papillary and reticular dermis interconnected by vertical plexuses. The nerve fibers are well formed. Collagen types III and V localize around vessels and nerves. Dilated channels of venous and lymphatic structures are seen in subcutaneous tissue.
Important events that occur in second trimester include completion of the formation of lanugo hair, synthesis of the hair (17–19 weeks EGA), completion of nail (20–22 weeks EGA) and keratinization of interfollicular epidermis (22–24 weeks). Proliferation of basal cells results in addition of three intermediate cells which are flattened towards epidermal surface. At the end of this phase, interfollicular epidermis keratinizes. Cornified cell envelope and lamellar granules are found. Keratohyaline granules with profilaggrin and filaggrin are identified with formation of spinous layer. By 22–24 weeks EGA, cells similar to true stratum corneum and granular layers are identified.
Merkel cells at a density of 1700 Cells/mm2 and Langerhans’ cells at 200 cells/mm2 are found in the epidermis. Melanosomes are transferred to keratinocytes in the fifth month of gestation. AF-1 and AF-2 associated with anchoring fibrils are recognized at this age. By 19–21 weeks hemidesmosomes, anchoring filaments and banded anchoring fibrils are well formed. In the dermis, interwoven, fibrous connective tissue, elastin and elastic fibers similar to elastin fibers of adult skin are recognized. Fibroblasts, mast cells, macrophages and smooth cells are also present.
In the hypodermis, by about 15–16 weeks, first stage of adipose tissue formation occurs. By 18 weeks, lipid droplets appear and at 20 weeks lobules of fat are formed. By the end of this stage, well-formed fetus with hair is present.
The epidermis is fully keratinized. DEJ, dermis and adnexae are fully formed. Before 26 weeks, Langerhans’ cells are localized only in the basal layer. From 27th week, they are also found in stratum spinosum. Large fat lobules are seen in hypodermis. Sweating response is limited but apocrine secretion begins. However, the structure and functions are not as matured as neonate. Babies may be born as preterm at this stage. The vasculature is less organized compared to the newborn.
UNIQUE FEATURES OF DEVELOPING SKIN
Periderm is the outermost transient cellular layer shed into amniotic fluid at the end of the second trimester. It may take its origin from either the basal cells or the amnion or it itself may be the original ectoderm. It undergoes changes resulting in epidermis development (Figure 1.1), but does not undergo keratinization. It is a layer that undergoes apoptosis.
Functions of periderm:
- Exchange of substances between the fetus and the skin e.g. drugs.
- It may add (secrete) materials into the amnion.
- It may protect the developing epidermis.
Regionalization in Developing Skin
Regional differences as in adult skin are well documented. However, similar differences in the expression of diseases may indicate multiple biopsies for the prenatal diagnosis.
It occurs in different structures at different times of gestation. The timing appears to follow a rigidly specified program.
By 10–11 weeks EGA, basal epidermal cells proliferate to form buds at specifically patterned sites. These buds grow into the dermis as hair germs and sweat ducts or fold to result in nail fold. This occurs in response to epithelial-mesenchymal interactions. Apart from this the nerves, vessels and adhesion molecules also play a role. The dermis is responsible for initiation and assembly, while epidermis determines the type of appendage.
By 70 days, the boundaries of the nail folds are established by proximal, lateral and distal folds. By 90 days, the dorsal ridge is formed. The nail fold invaginates deeply into the dermis resulting in dorsal and ventral layers. The ventral fold becomes the nail matrix. Nail is the earliest structure to keratinize in utero. By 15 weeks, a fragile nail consisting of cells form nail bed and by about 19 weeks, cells from both nail bed as well as matrix form nail.
Eccrine Gland Formation
By around 10–12 weeks EGA, sweat glands are initiated on the palms and soles. Primary epidermal ridges organize from the basal layer. Mounds of mesenchyme form volar pads. These are transient and disappear by the end of first trimester. Sweat glands develop on the body late in the second trimester.
Formation of hair follicle begins on the head and face around 70–80 days EGA and proceeds cephalo-caudally. There are different stages of formation of hair follicle (Figure 1.2).
The induction, development, maintenance and regression in adults are dependent upon an association of follicle epithelium with dermal mesenchymal cells which form dermal papilla. Cells from the basal layer bud into the dermis to become hair germs. Condensed mesenchymal cells associate closely with the germs. Around 13–14weeks EGA, hair pegs are formed. It consists of an inner cuboidal and an outer columnar layer associated with the basal lamina surrounding the follicle and continuous with that of the interfollicular epidermis. Merkel cells are present among outer root sheath keratinocytes. Each hair peg is cylindrical and later develops into infundibulum, isthmus and bulb. Elongated core cells in the neck of the follicle continue into the epidermis, in between the basal and intermediate layers. This is the hair tract and presumptive hair canal.
The distal end of the hair peg flattens and the epithelial cells along this basal border elongate to form matrix. Inner root sheath and hair cone are formed. Melanocytes aggregate in the matrix and produce melanin ahead of other sites. Between 15 and 17 weeks, bulbous hair peg and bulges for arrector pili muscle, sebaceous gland and apocrine glands are formed.
- Disorders of keratinization can be identified by using chorionic villus biopsy, amniocentesis and fetal skin biopsy at various stages of development.
- Density of melanocytes can be useful in early detection of tyrosinase-negative oculocutaneous albinism.
- Capillary malformations in hereditary hemorrhagic telangiectasia may result due to mutation in TGF-β binding protein.
STRUCTURE OF THE NEWBORN SKIN
The newborn skin has similar structural composition as that of adult. However, there are a few salient differences. DEJ in neonates, although complete, is flat without ridges. Dermis is also relatively immature compared to adults. Reticular dermal collagen is in smaller bundles, elastic fibers are finer, less mature and it is cellular consisting of more fibroblasts (Table 1.2). Functional, biochemical and even structural maturity may not be achieved until several years of age.
Skin is made up of epidermis and dermis (Figure 1.3) which contain epidermal appendages, blood vessels and nerves providing nutrition and integration to these tissues. Epidermis is made up of keratinocytes, Merkel cells, melanocytes and Langerhans’ cells. DEJ is a complex structure which supports epidermis and transports molecules bi-directionally. Dermis consists of mast cells, blood vessels, lymphatics and appendages.
Keratinocytes form more than 90% of the cells. Epidermis comprises of basal, spinous, granular and horny layers. Melanocytes, Merkel cells and Langerhans’ cells are present among them.
It is known as stratum basale or germinativum. The basal keratinocyte is a columnar cell, which rests on basement membrane (hemidesmosome).
It has desmosomal junctions, gap junctions, adherens junctions with other basal keratinocytes and spinous keratinocytes, and desmosomal junctions with Merkel cells. It also borders Langerhans’ cells and melanocytes. Keratins K5 and K14 are hallmarks, although K15 can be present in small amounts. This acts as a renewing source for life-time of an individual.
Stratum spinosum consists of 3 to 4 layers of more flattened cells containing large bundles of keratin filaments. In addition to the keratin filaments of basal layer, newly synthesized K1 and K10 are present. Desmosomes are prominent and shrinkage of tissue during processing gives spine-like appearance. Lamellar granules are 300–500 micrometers in diameter, membrane-bound organelles formed in the Golgi bodies. These contain carbohydrate complexed with proteins, lipids and hydrolytic enzymes. These help in barrier function.
In stratum granulosum the cells are arranged in two to three layers and contain keratohyalin granules. Lamellar granules are released which fuse and aggregate with the plasma membrane in between granular and horny layers.
Filaggrin forms in this layer and may have a role in aggregating keratin filaments. Transitional layer in between granular and horny layer comprising of cells with heavily convoluted nucleus may be present. Apoptosis is initiated in this layer.
This is the outermost layer of cells comprising of dead cells. It varies form 15 layers on general skin up to hundreds of layers on palms and soles. The thickness is similar in children and adults. Within plasma membrane, a highly cross-linked structure ‘the cornified cell envelope’, formed by epidermal transglutaminase, loricrin, keratins, pancornulin and other proteins is present. Epidermal ceramides are cross-linked across the cell membrane to the envelope which may stabilize the extracellular lipid layer.
In the epidermis, Melanocytes are located in the basal layer. Each melanocyte is linked with 36 basal and spinous cells forming epidermal melanin unit (EMU). Melanocyte is a round to oval cell with refractile brown granules in the cytoplasm. Melanosomes are complex organelles and the site of melanin production. They contain tyrosinase and lysosomal enzymes. They are divided into four stages based on the pigmentation.
Langerhans’ cells are regularly distributed suprabasally at a density of 460–1000 cells/mm2. They have a convoluted nucleus and the Birbeck granules. Surface markers include class I and II HLA-antigens, S-100 protein and others.
Merkel Cells these are located individually in basal layer or in larger groups as touch receptors in association with myelinated nerves in epidermis, hairs and mucosae. They contain dense core granules and simple keratins. K20 is relatively specific for these cells.
Hair follicle is divided into four segments, infundibulum, isthmus, stem and bulb (Figure 1.4). The pilosebaceous duct in the infundibulum is lined by a stratified keratinzed epithelium. The bulge is the site of expansion of outer root sheath cells and is at the insertion of the arrector pili muscle. This is the site of stem cell population of the follicle. The bulb contains the germinal cells of the follicle, melanocytes, langerhans’ cells and Merkel cells. Dermal papilla is located in the concavity of the bulb. The inner root sheath ends at the junction between the isthmus and the infundibulum. The cells of the innermost sheath synthesize trichohyalin but the outer root sheath cells do not keratinize. Fully formed hair consists of inner and outer cuticular layers, cortex and medulla. Hair provides protection, sensory perception and adds to the cosmetic appearance.
Nail consists of nail matrix, nail bed, nail plate, lateral and posterior folds, lunula, cuticle and hyponychium (Figure 1.5).
Nail matrix differs from epidermis and hair in producing cells that retain nuclei. Melanocytes are present in the lower two to four layers of matrix. It protects the underlying structures from physical trauma as well as infections. Nails can be used for scratching.
They are distributed all over the body. The highest density is on the palms, soles and the forehead. The secretory coil is in the reticular dermis or subcutaneous tissue. The secretory portion consists of pyramidal, clear, dark and myoepithelial cells. Clear cells secrete water and electrolytes. The eccrine duct has two layers in the dermis. The intraepidermal portion of the duct lining is keratinized at the outermost sweat pore. The outer cells have prominent microvilli and mitochondria for reabsorption. The innermost cells form a “cuticular border” with microvilli, microfilaments and intermediate filaments. Clinically, sweating starts on 1st day after life.
These are large, coiled tubular glands situated deep in the dermis. They occur over face, scalp, axilla and anogenital regions. Modified glands are present in eyelids (Moll's gland), ear canal and areola. It consists of secretory and myoepithelial cells. The duct contains three layers of cells.
They are associated with hair follicle. The density is highest over face, scalp and upper chest. Modified glands may be present in eyelids, lips, buccal mucosa, glans and prepuce. They secrete sebum which is oily.
Dermo-epidermal Junction (Figure 1.6)
This consists of dermal ridges and papillae. Electron microscopy shows lamina lucida, lamina densa, anchoring filaments, anchoring fibrils, the reticular lamina and sub-epidermal region of the papillary dermis. Hemidesmo-somes span the cytoplasm of keratinocyte and portions of lamina lucida. It includes the bullous pemphigoid antigens.
Dermis consists of papillary and reticular zones. Reticular lamina (compact zone) in superficial papillary dermis consists of fine dense collagen. In contrast, reticular dermis has elastic fibers, thicker collagen bundles and a higher density of vessels than papillary dermis. They contain fibroblasts and dermal dendrocytes. Fibroblasts are the source of the extra-cellular structural molecules of the dermis.
FUNCTIONS OF THE NEWBORN SKIN
Skin protects against the trauma due to blunt objects. Dermis plays a major role, although stratum corneum and subcutaneous tissue also play a part.
Stratum corneum acts as an effective physical barrier to prevent entry of toxic substances into the skin. Although the thickness and layers of stratum corneum in neonates is comparable to that of adult, it is functionally immature. Hence care should be taken during topical applications of soaps, aniline dyes, hexachlorophene, phenol and other toxic substances. Further, infants have three times more surface area per unit weight compared to adults, resulting in toxicity of topical applications.
An intact stratum corneum prevents invasion by microorganisms. Sebaceous lipids are known to have antibacterial properties. Anti Microbial Peptides (AMPs) such as defensins and cathelicidins present in the epidermis can destroy gram-positive and gram-negative organisms.
MAINTENANCE OF HOMEOSTASIS
Skin plays an important role in thermoregulation by heat loss or conservation. Heat can be lost through radiation, convection, conduction and evaporation. Dermal vasculature plays an important role. In high environmental temperatures, eccrine sweating plays a role. In neonates, since the barrier function is immature, the rate of heat loss by evaporation may exceed the baby's heat production.
Protection from ultraviolet rays is provided by melanin barrier in the epidermis and a protein barrier in the stratum corneum.
SYNTHESIS OF ESSENTIAL NUTRIENTS
Vitamin D synthesis occurs in the spinous and the basal layers, under the influence of ultraviolet rays from sunlight.
Skin acts as an immunologic organ, as it contains macrophages, Langerhans’ cells and dermal dendrocytes participating in the cell-mediated response. It also seeks to check the invading pathogens by immunologic mechanism.
SKIN OF THE PREMATURE INFANT
A premature infant is the one who is born before 37 weeks of gestation. It also refers to infants with less than 2.5 kg of weight. Extreme prematurity refers to babies with less than 1.25 kgs of body weight. The skin of the premature infant is that of the third trimester fetus. The skin is immature in both structural and physiologic properties. The skin of a newborn infant of 26 weeks’ gestation is pink and relatively transparent; the underlying blood vessels are readily seen with moist surface. The epidermis although structurally complete, is relatively thin with only 5–6 layers of cells in stratum corneum and is poorly keratinized. Glycogen is still retained and barrier is poorly developed. Also, as the surface area per unit weight is seven times that of an adult, absorption and toxicity of topically applied medications can occur. Lack of enzymatic activities to detoxify substances, also adds to this. Nonspecific factors such as increased permeability of the skin and decreased gastric acid content of the stomach also may reduce neonatal immunity. Transepidermal water loss is also increased in preterm skin. It is inversely proportional to gestational age. There are only a few mature Melanosomes in the melanocytes. The development of DEJ is complete but flat. The papillary dermis is edematous and the bundles of collagen fibrils are smaller and more widely spaced. The dermis is about three-quarters of the thickness of adult dermis. Fine collagen fibers and small-sized collagen fiber bundles give the dermis a highly cellular and delicate appearance. Elastic fibers are tiny, sparse and immature. Lack of subcutaneous fat, poor autonomic control of cutaneous vessels and functionally reduced sweating contribute to poor thermal regulation. Premature infants have increased cutaneous gaseous exchange i.e. increased oxygen absorption and carbon dioxide evaporation.
SKIN CARE OF INFANTS
SKIN CARE IN THE PREMATURE INFANT
Skin matures rapidly in preterm infants after birth. Goals of therapy include immediate access to the infants, heat retention, fluid and electrolyte balance, prevention of infection and rapid epithelial maturation. They are preferably nursed in closed incubator and kept warm. Environmental conditions in these units are potentially harmful, resulting in scarring. Cosmetically or functionally significant lesions may be caused by different procedures including skin stripping due to adhesive tape. Neonatal staff must be aware of this potential long-term complication.
Disinfection: Catheter-related septicemia is most commonly caused by coagulase-negative Staphylococci. To prevent this, hand washing by staff and parents must be advocated. Two consecutive10 second wipes with chlorhexidine, alcohol or povidone-iodine or a longer duration of cleaning for about 30 seconds is more effective than a single 10 second wipe.
The Incubator: Regular change of infants’ posture reduces the risk of skin erosions and bedsores. Fingers and toes must be kept visible. Catheters or needles should be secured with a transparent tape to detect extravasation. Scarring alopecia can occur after extracorporeal membrane oxygenation or hypoxaemia-hypoperfusion. Non-blanchable erythema and disruption of epidermis are early indicators of pressure sore and demands postural change.
Transcutaneous oxygen monitors: These should not be left in place for more than one hour without surveillance. Non-blanchable erythema and hyper pigmented skin craters following prolonged contact can occur. Karaya electrodes seem to be less traumatic. Placement of electrodes on the limbs may facilitate frequent auscultation.
Minimal use of tape and adhesive: Tapes and adhesives should be used on small areas of skin and removed gently with warm water soaked gauze and diluted soap but not alcohol, which may irritate. A pectin-based skin barrier may be used, when frequent application and removal of adhesives is needed.
Emollients: Emollients are safe and effective in neonatal peeling and scaling dermatitis. They decrease fragility, improve wound care and help to protect infants. Vegetable oil (e.g. olive oil), lanolin and petrolatum – based ointments reduce scaling and fissure, and enhance cutaneous hydration.
Transparent cover: Use of a transparent covering over the isolette on small premature infants may help to decrease insensible water losses.
Reduction of water loss: Water loss can be reduced by humidification of the surrounding air, use of plastic bubble blankets, heat shields or topical application of paraffin.
NEONATAL SKIN CARE
After birth, neonatal skin is exposed to air, temperature changes, friction, microbes etc. Maintaining skin integrity and preventing exposure to toxic substances in childhood assures healthy skin for several years ahead.
At birth, microbial colonization of skin is nil. Within a few days, aerobic flora colonizes over the groins, axillae and scalp. Coagulase-negative Staphylococci (Staphylococcus epidermidis) is the commonest followed by S. aureus. The latter is usually due to contamination by the mother or nursing staff.
SKIN CARE AT BIRTH
Removal of Vernix Caseosa
At birth, newborn skin is coated with vernix caseosa, blood, meconium and cellular debris. Premature infants tend to have less vernix than term babies and the post mature little or none. There is considerable inter-individual variation. It is unclear whether vernix gives mechanical or microbial protection. It is wiped off with a clean towel after birth.
Washing and Bathing
A bath cleans the infant completely. It should not last for more than five minutes. Infants may be bathed immediately after birth. The water should be sterilized by boiling, but the temperature of the bath -water should not exceed 37° C. A solid or liquid soap or a syndet may be used to clean the baby. Bubbles bath used can irritate or dry the skin. Soap should be thoroughly rinsed, and the baby patted dry especially in folds.
Napkin should be changed frequently, at least at each nursing and feeding time. Baby should be washed in lukewarm water and dried thoroughly. Partial occlusive agent like mineral oil application can act as a physiological barrier. Skin should be thoroughly air-dried each time the diaper is changed. Powder may be applied in the skin folds after drying. Soaps should preferably be avoided or they should be mild. Nappies should be home laundered with mild detergents. Nappy pads with cotton padding are more suited.
Shampoos may be rarely used. On first signs of seborreic dermatitis, application of mineral or animal oil limits the spread.
They should be trimmed short and kept clean.
Cotton swabs soaked in boiling water may be used without injury to the canals.
After birth, the umbilical cord dries out and falls within 5–10 days. Certain products containing eosin or other stains are applied. They act as drying agents rather than as antiseptics.
SKIN CARE OF THE TERM BABY AND INFANT
A large number of over-the-counter cosmetics for children are available in the market. In addition to the prescribed medical treatment, infants’ skin is at risk by these cosmetics.
Role of Cosmetic Products
Several types of products are used like detergents in the form of soaps or shampoos, antiseptics, emollients etc.
Detergents: Detergent is a substance capable of cleaning the skin by removing impurities like dust, greasy substances and micro-organisms. These act by reducing surface tension between water and air, creating a foaming effect. Foaming power is directly proportional to skin damage. Its usage should be followed by a thorough rinsing.
Soaps are alkalis with delipidating effect on the skin. In hard water, soaps tend to precipitate.
Syndets: These are composed of tensioactive cleansing agents with detergent quality, produce little foam and minimal irritation. They should be used with moisture as an additive.
Bubble Bath Products: Prolonged bath may irritate the genital mucosa.
Shampoos: These contain anionic tensioactive agents which ensure adequate cleansing. The pH should be equivalent to that of tears and have low ocular irritation index. Medicated shampoos containing selenium sulphide, zinc pyrithione and ketoconazole may be used for seborreic dermatitis.
Antiseptics: Risk of toxicity due to absorption is high with these topical medications, due to increased surface area, immature barrier and other factors. Biguanides and amidines are better for use in infants. Dilution, application time and rinsing conditions need to be determined since the action is time-dependent.
Emollients: Emollients can be applied on normal as well as pathologic skin and reduces imperceptible water loss.
Protective creams: Protective creams are used to reduce the risk of irritation, particularly napkin rash. These contain a fatty phase, an aqueous phase, a surfactant, zinc oxide, scents and preservatives. They can paradoxically increase occlusion and cause napkin dermatitis. Early sensitization can occur with certain preservatives.
Powders: These are used to prevent maceration over the skin folds in infants. Excessive use may cause miliaria
Role of Massage
Touch helps in growth and development of the child. Massage with oil is better than without. The oil should be smooth, of optimum viscosity, frictionless and non-occlusive. Mineral oil is one of the best ingredients. Gentle massage can be practiced from 10th day till 10th year of life. Massage given by the mother helps in developing bondage between the mother and the baby. Complete head to toe massage can be given daily.
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