Description of the condition
Dry skin is a common occurrence in the first few months of an infant's life (Saijo 1991). Dry skin has been defined as “a cutaneous reaction pattern reflecting abnormal desquamation of diverse etiologies” (Madison 2003). In normal skin, corneocytes are shed from the skin in small enough quantities that they are not visible to the naked eye; however, in dry skin, the skin appearance becomes rough and flaky if this normal process is disturbed in any way. In an infant, this is a normal process of adaptation to life outside the uterus.
Atopic eczema (synonym atopic dermatitis) is an inflammatory skin condition characterised by dry and scaly skin, redness, blistering and itching. It affects up to 30% of children aged 2 to 15 years in the UK (Gupta 2004). Affected children are also predisposed to allergic asthma and allergic rhinitis (Gustafsson 2000). It is suggested that approximately 60% of sufferers develop atopic eczema in their first year of life (Bieber 2008). Prevalence has increased to this current level from approximately 5% of children in the 1940s (Taylor 1984). During that time the genetic structure of skin has not changed; however, the way that we care for an infant’s skin has changed, with an increase in use of soaps, other harsh detergents and oils (Cork 2009; Danby 2011a).
Infant skin is physiologically different to adult skin. The stratum corneum is 30% thinner and the epidermis is 20% thinner in infants than in adults (Stamatas 2010). This difference in skin structure results in increases in permeability and dryness in infant skin. Infant skin is also more vulnerable to the use of topical treatments, as the ratio of infant body surface to body weight is higher than that for adults; hence, the risk that such therapies will be absorbed through the skin is greater in infants than in adults (Nikolovski 2008). As the infant skin barrier continues to develop during the first year of life (Stamatas 2011), infants are vulnerable to this risk throughout this period. Infant skin is prone to an increased rate of transepidermal water loss (TEWL) and reduced stratum corneum hydration because it contains fewer lipids and natural moisturising factors, and less melanin than adult skin (Chiou 2004; Nakagawa 2004). Infants may also experience a weakening of the skin barrier due to their elevated skin surface pH. High skin surface pH (low acidity) results in increased activity of proteases, which breakdown corneodesmosomes (the supportive component of the stratum corneum), and hinders the activity of enzymes that are required for lipid processing (Hachem 2003; Cork 2009).
These differences in both structure and function between infant and adult skin suggest that infant skin is more vulnerable to environmental factors, including infant skin care products. The use of some topical oils and emollients on infant skin may therefore contribute to the development of adverse skin conditions, including atopic eczema, whereas other topical oils may have a positive effect and prevent the development of this condition (Danby 2011a; Danby 2011b; Danby 2013).
Description of the intervention
Parents want to use skin products that make their infant look and smell nice (Lavender 2009; Furber 2012). The application of oil is commonly recommended by health professionals to new parents for use on their newborn infant’s skin (Lavender 2009; Cooke 2011), in order to prevent or treat dryness or for massage. The use of emollients is not commonly recommended; however, parents have the choice of a diverse range of emollient infant skin care products from numerous manufacturers. In a UK national survey (Cooke 2011), 52% of maternity and neonatal units recommended the use of oil; 82% of these units recommended olive oil to parents for use on their infant’s skin and 20% recommended sunflower oil. Health professionals, such as midwives and health visitors, believe these oils to be natural and, therefore, not harmful to infant skin (Lavender 2009). Infant skin conditions can cause parental anxiety (Adalat 2007). Parents will often adhere to advice given to them by health professionals with regard to the care of a newborn infant (Lavender 2009).
How the intervention might work
Some oils have been shown to have a positive effect on skin barrier function (Darmstadt 2004; Darmstadt 2008; Danby 2013), whereas others may impair this function (Naik 1995; Darmstadt 2002a; Jiang 2003; Danby 2013). Research has shown that olive oil of a certain composition (i.e. a high ratio of oleic acid to linoleic acid) may adversely affect skin barrier function in mice (Darmstadt 2002a; Jiang 2003) and adults (Naik 1995; Danby 2013). This composition of oil disrupts the lipid structure of the stratum corneum, and is a potential risk factor in the development or exacerbation of atopic eczema. Optimal sunflower oil (i.e. a high ratio of linoleic acid to oleic acid) has been shown in the same population to promote skin barrier repair (Darmstadt 2004; Darmstadt 2008; Danby 2013).
The use of emollients or moisturisers is common in skin care regimens. They act by preventing water loss or by actively hydrating the skin (Elson 2011). The main reason to use emollients in skin care is to protect the integrity of the skin barrier. For healthy term infants, this is not clinically necessary; however, those infants at risk (such as those with a family history of atopic eczema) may benefit from the regular use of emollients (Frieden 2011). An oil is also an emollient that helps to prevent water loss and lubricates the skin.
Why it is important to do this review
Societal interest in ‘natural’ products is high (Allemann 2009), especially in parents of newborn infants (Cottingham 2007). There is a readiness among parents to use oil for infant skin care, and a readiness among maternity professionals to recommend it. There is a misconception that because a product is ‘natural’ it must be ‘safe’ (Lavender 2009; Bedwell 2012). Oils have been used in the cosmetic, pharmaceutical and perfumery industries for many years. Although oils are governed by guidelines for the testing and research of cosmetics (Council of the European Communities 1976), these are not as rigorous as those governing the use of medicines in humans (Department of Health 2004). This means that oils have been used as medicinal and homeopathic remedies for many years without any collection and analysis of toxicological data. The infant skin surface area in relation to body weight is high and absorption is relative to the surface area exposed (Rutter 1987). Topical applications may cause irritation, damage or systemic effects through absorption of the oil in to the body.
Infection is one of the leading causes of neonatal morbidity and mortality in low-resource countries (Darmstadt 2002a). The vulnerability of infant skin and the use of oils that may be harmful, combined with poor hygiene conditions, have the potential for increased hazards of infection. Nosocomial sepsis is more common in preterm infants, in whom the stratum corneum is not fully mature (Conner 2009) and the skin does not have the protective benefit of vernix (Yoshio 2003), than in term infants. Several studies (Darmstadt 2002b; Darmstadt 2004; Edwards 2004; Darmstadt 2005; Darmstadt 2008; Kiechl-Kohlendorfer 2008) and a Cochrane systematic review (Conner 2009) have considered topical applications for preterm infants, but no review has considered the evidence in term infants.
We know that 45% and 60% of atopic eczema cases occur in the first six months and year of life, respectively (Bieber 2008). This period of time is when midwives, maternity workers and other infant health professionals have the most influence with parents. Health professionals find it difficult to give evidence-based advice to new parents, as there is insufficient evidence to guide practice. It is therefore important to systematically review what evidence there is, to provide a high-quality basis for clinical practice and informed decision-making. Some oils are potentially harmful; however, others may provide some benefit. Given the rise in the prevalence of atopic eczema, it is timely to evaluate current evidence in order to provide the most appropriate advice for parents and health professionals.
This review will assess the effects of topical oils and emollients in the prevention or treatment of dry skin compared to the use of alternative oils and emollients or no treatment in term infants. The review will complement the body of work held in theCochrane Database of Systematic Reviews, which includes reviews such as those investigating the prevention of infection in preterm infants (Conner 2009; Seliem 2009) and the prevention of napkin dermatitis in infants (Davies 2009).
A systematic review will provide:
an evidence base to inform parents and health professionals in their practice with healthy term newborn infants, rather than remain in confusion regarding which oil or emollient, if any, to recommend or use; and
highlight any area that requires further investigation.