Infant skin cleansing is a controversial topic and one about which proponents of different regimes have strong opinions (Hugill, 2014). Nappy rash and nappy dermatitis are broad terms used to describe inflammatory changes in the skin of the nappy area (lower abdomen, buttocks, perianal and perineal areas) (Buckley et al, 2016). This article describes factors implicated in causing nappy dermatitis and explores nappy area care practices that could help to prevent the condition. Having an understanding of this topic is important for midwives as they are often asked by parents about what is best in this aspect of infant care, and they need to be able to provide evidence-based advice.
Statistics reveal that nappy dermatitis is a common disorder affecting both sexes equally, with an incidence peaking at around the age of 9–12 months (Blume-Peytavi et al, 2014). While most children might expect to have experienced an episode before they stop wearing nappies, precise figures show considerable variability (Garcia Bartels et al, 2012; Panahi et al, 2012; Yonezawa et al, 2014). This situation reflects different data collection timeframes, study populations and definitions (Buckley et al, 2016), but also possibly differences in infant hygiene practices. Exclusive breastfeeding may confer some protective advantage. The incidence of nappy rash and dermatitis is often reported as lower in exclusively breastfed infants—an observation that may reflect the lower incidence of infective diarrhoeas and the more acidic nature of the stool compared to formula-fed infants (Stamatas and Tierney, 2014).
Pathophysiology
Infant skin has unique features that affect its water handling and barrier properties (Stamatas and Tierney, 2014). After birth, the skin undergoes a prolonged and complex process of physiological, anatomical and microbiological maturation (Visscher et al, 2015). These changes can be observed though physiological measures such as hydration, trans-epidermal water loss (TEWL) and pH. The clinical significance and predictive value of these measures is indeterminate, but during this period the skin is particularly prone to sensitisation and damage (Garcia Bartels et al, 2012; Yonezawa et al, 2014).
Diagnosing rashes in infants is an important skill. It is imperative to correctly differentiate nappy dermatitis from other conditions to ensure correct treatment (Coughlin et al, 2014a). For example, allergic contact dermatitis owing to residual detergent in reusable nappies, or dyes in disposable nappies, or ingredients in care products, require different corrective measures (Coughlin et al, 2014a). Midwives should familiarise themselves with the features of pathological (e.g. sepsis-related) and common physiological (e.g. miliaria rubra) rashes in infants, in order to reassure parents and ensure timely specialist advice and referral.
Current ideas about the aetiology of nappy dermatitis suggest it is triggered by a cascade of factors that interact to impair barrier functionality and predispose the skin to harm (Shin, 2014). Precursors include over-hydration of the stratum corneum owing to prolonged wetness and having an alkaline skin pH (Stamatas and Tierney, 2014). This can make the skin more susceptible to damage from other factors, for example, over-vigorous rubbing during cleaning can lead to stripping of macerated skin layers. Other factors involved in causation include: irritation through prolonged contact with faecal lipase and protease enzymes, unbalanced skin biome, and contact with some hygiene products (Coughlin et al, 2014a; Stamatas and Tierney, 2014). Together, these factors raise skin pH, damage lipids in the stratum corneum and impair skin integrity. Prolonged exposure of compromised skin to stool protease enzymes causes further harm (Blume-Peytavi et al, 2014). Fungal (Candida albicans) and bacterial (especially Staphylococcus and Streptococcus genera) growths are frequently isolated from swabs of inflamed skin in the perianal area. However, in practice it can be unclear whether these are opportunistic or causative infections (Coughlin et al, 2014a).
Cleansing
A goal of nappy area cleaning is to remove faeces and urine without irritating the skin (Coughlin et al, 2014b). Other aims may also feature, such as promoting skin health and aiding skin barrier repair. Ensuring effective hygiene of the nappy area is a universal issue, but nappy area care varies internationally (Thaman and Eichenfield, 2014), suggesting there is no single view about the best method. Furber et al (2012) suggest that confidence in the chosen method is an important factor in parental decisions about nappy area cleansing. When things go awry and infants develop inflammation, parents often experience guilt (Furber et al, 2012). Midwives need to be mindful of how they communicate information about the possible causes of any rashes, as it could imply poor skin care—and, by extension, poor parenting—and might affect the emotional wellbeing of parents.
The rhetoric that water is the best choice of cleansing agent is deeply entrenched, though water's innocuity is questionable given the role of skin hydration in nappy dermatitis. Blume-Peytavi et al (2014) in a review of 13 nappy care studies conducted between 1970 and 2012 concluded that cleaning using water and wash cloth or commercial wipes had comparable physiological effects on the skin. Newer evidence about the safety, efficacy and non-inferiority of specially formulated infant care products (for example, Lavender et al, 2012; 2013) also challenges this viewpoint and informs contemporary professional consensus (Blume-Peytavi et al, 2016).
Baby wipes are popular among parents, with many citing ease of use and convenience (Lavender et al, 2009). Some earlier generations of wipes contained considerable amounts of cleaning agents, perfume and alcohol and were linked to skin irritation (Blume-Peytavi et al, 2016). Most modern wipes are made from manmade fibres and include water, synthetic detergents, emollients, pH stabilisers/adjusters, and preservatives as their ingredients. Modern formulations are generally well tolerated, though some preservatives are known to cause allergic dermatitis in susceptible people (Coughlin et al, 2014b). One study (Lavender et al, 2012) of term infants (n = 280) compared measurements of skin hydration, TEWL and pH over a period of 4 weeks from birth between groups randomised to either use wipes or cotton wool and water for cleaning the nappy area. The authors reported no differences in physiological measures between the two groups and concluded that wipes were not inferior to the more traditional method of cleansing.
There is observational and some empirical evidence that some ingredients used in preparations applied to the nappy area skin can protect the skin and aid healing. For example, zinc oxide (preservative-free) and petrolatum compounds are considered safe and effective barrier ointments (Blume-Peytavi et al, 2014). Other ingredients such as vitamins A and E, medical clays (bentonites) and herbal plants like chamomile, aloe vera and calendula are widely used in commercial products for their anti-inflammatory and bacterial and Candida-growth inhibition properties. However, there is little independent empirical data about the use, efficacy and safety of topically applied naturally derived products (Davies et al, 2005). In part, this is because the raw materials originate from different sources and are formulated differently, which negates direct comparison.
Evaluating the effectiveness of interventions to prevent and treat nappy dermatitis is fraught with methodological difficulties. While we have reliable measures of skin integrity readily available, their relationships to clinically important conditions and predictive power is underdeveloped
In sensitive people calendula and chamomile can cause allergic reactions, but commercial products are generally well tolerated. Small-scale clinical trials comparing the efficacy of these ingredients on recovery from nappy dermatitis have been carried out (Panahi et al, 2012; Afshari et al, 2015; Mahmoudi et al, 2015). However, these trials suffer from a number of methodical limitations. For example, sample sizes were small (n = 66, 90 and 100, respectively), included children aged between 1–36 months, and did not include information about routine nappy and general skin care. Given what we know about the effects on skin integrity of different care regimes and infant skin maturation during the first 12 months after birth, it is questionable whether these studies can be generalised.
Inflamed skin is more permeable, and there is some concern that intended and unintended ingredients (contaminants) might be absorbed. In the US, media reports and government agencies linked some preparations of bentonite with excessive lead contamination (US Food and Drug Administration, 2016a; 2016b). Though the risks of lead poisoning were uncertain, parents were advised to discontinue using the products. Advice about homemade preparations to treat and prevent nappy dermatitis is readily available, but their use is not without risk. Some home remedies recommended on social media such as vinegar, corn starch and baking soda rely on scant evidence and may be harmful if misused. For example, topical applications of diluted vinegar (intended to reduce skin pH) may be caustic or painful when applied to inflamed skin. Midwifery advice to use such interventions is probably best avoided.
Nappies undoubtedly meet the hygiene needs of infants but their occlusive nature concomitantly increases local humidity, hydration and pH (Garcia Bartels et al, 2012), factors implicated in nappy dermatitis (Stamatas and Tierney, 2014). Odio and Thaman (2014) suggest that disposable nappy design and manufacturing technology could improve skin health. A 2006 Cochrane review (Baer et al, 2006) concluded that there was not enough evidence to support or refute the claim that disposable nappies offered protection against developing nappy dermatitis. However, since this review was published, manufacturing technology for disposable and reusable products has advanced.
Parents choosing which type of nappy to use are faced with a plethora of advertising claims and counter-claims. According to Odio and Thaman (2014), disposable nappies have advantages over traditional reusable nappies, including convenience, comfort, and hygiene. Proponents of modern reusable products refute these claims being unique. In addition, everyday cost and environmental footprint are often cited as less advantageous features of disposables, though the economic argument is less clear when the monetary and environmental costs of laundering reusable nappies are factored in. It has been postulated that the inclusion of super absorbent gels (reducing skin moisture), petrolatum-based lotions (improving skin integrity) and breathable outer layers (reducing local humidity) into thinner nappies with a better fit to the body's contour has led to a reduction in the presence of erythema and severity of nappy dermatitis (Odio and Thaman, 2014). However, the exactness of any relational correlation is contestable because declines in the incidence and severity of the condition also map with the development of newer infant cleaning products and their wider adoption by parents into everyday skin care regimens.
Many commentators advocate for the benefits of nappy-free time by exposing the nappy area to air to aid healing and drying. How long this time should last is unstated, and this leaves parents with uncertainty. One study (Furber et al, 2012) reported that nappy-free time ranged from 10 minutes to several hours per day; no explanation was offered for this variation. While this advice lacks detailed evidence, providing the infant is kept warm, it is unlikely to be harmful and also provides an opportunity for parent–infant interaction.
Evaluating the effectiveness of interventions to prevent and treat nappy dermatitis is fraught with methodological difficulties. While we have reliable measures of skin integrity readily available (hydration, TEWL, pH), their relationships to clinically important conditions and predictive power is underdeveloped. Visual observation and description of the skin remains the main tool for assessing skin health. Rating scales grading the severity and extent of inflammation exist (e.g. Coughlin et al, 2014b; Stamatas and Tierney, 2014; Buckley et al, 2016) but few have been validated. In general, more research is needed to clarify the predictive relationships between skin physiology measures and skin disorders, and refine assessment tools to better evaluate the effects of treatment or preventive strategies. Doing this will inform the production of robust, evidence-based guidance for parents and health professionals.
Conclusions
Appropriate skin care practices that promote skin barrier functionality, protect the skin and aid healing are essential to prevent and treat nappy dermatitis. Despite a plethora of recommendations and advice on this matter, what constitutes best practice is moot. There is not enough evidence from good-quality studies to unequivocally determine what constitutes optimal nappy area care. Current professional consensus and evidence evaluation suggests that:
Further research is required in this area, to determine the evidence for best practice and form recommendations for both health professionals and parents.