The January column reviewed the pathogenesis of diaper dermatitis (DD)1,2 and noted multiple factors are associated with diapers, bowel movements, and urination.3 Persistent moisture keeps the pH elevated and the skin prone to maceration. Stool enzymes (lipase and protease) are active in the presence of an alkaline pH, leading to excessive outer lipid breakdown and defective stratum corneum (SC). Microscopic skin breakdown allows chemical/microorganism entry and inflammation, edema, erythema, further skin injury, and eventually a denuded outer epidermis.1,2
The pathophysiology of DD explains the rationale behind the products used to treat it. The majority of DD is irritant contact dermatitis.3 This condition often presents as nonspecific erythema that is poorly demarcated with occasional papules, vesicles, and erosions. Skin folds are spared, whereas a yeast/bacterial dermatitis (an infectious etiology) will involve folds of the thigh and groin with bright red papules and satellite lesions. The goal of treatment is to allow restoration of the SC despite exposure to irritants by providing a robust but easily removable barrier or semipermeable film over the skin.
Various preparations in the form of creams, gels, and ointments are available on the market. Ointments are often preferred due to their superior ability to penetrate SC.
Occlusives. These products are applied as a hydrophobic layer on the skin and provide an exogenous barrier to water loss.4 Occlusives prevent evaporation, which can be detrimental in very preterm babies in whom water vapor accumulation under the SC will cause breaks in the outer layer; using a thin layer of the product may alleviate this concern. The most common occlusive is petrolatum; it may be mixed with lanolin, zinc, or dimethicone. Dimethicone, an oil-free silicone, is the second most common occlusive4; it is a thinner occlusive, with a better water vapor permeability than petrolatum and is less occlusive. Both pertrolatum and dimethicone can act as emollients.
Emollients. Emollients are moisturizers that improve skin texture by filling in the crevices between corneocytes, adding softness. Natural oils often are added to diaper creams to provide essential fatty acids (eg, linoleic acid) that can be oxidized to eicosanoids, which serve as important signaling and anti-inflammatory molecules.4
Natural oils. Clinicians must be particularly aware of the addition of multiple “natural oils.” Many are known for their irritant potential. Oils with high oleic acid content (ie, olive, mustard, corn, palm, soya bean oils) are pro-inflammatory and not recommended for newborns. Use of oils with high linoleic content (eg, sunflower, safflower and apricot oils) is encouraged.
The term natural has been capitalized upon by industry, but “natural” does not mean it is nontoxic or safe. Synthetic products may be safer because concentrations of specific chemicals are known and regulated, where “natural” products are not regulated by any governing body. “Organic herbal” products also should be used with caution; they may have been grown without fertilizers or pesticides, but “organic” plants contain the same toxic chemicals as a synthetically produced chemical structure in an unregulated quantity. Herbal or natural products, such as tea tree, lavender, mint, aloe, and yarrow, are some of the most allergenic substances among neonates. For example, aloe, arnica, goldenseal, and calendula are known for their allergic contact dermatitis properties. Additionally, scant data are available for these products to guide use on pediatric skin, and caution is warranted. I teach caregivers to read labels carefully and determine the meanings of long, unpronounceable chemical names.
Many products have fragrance added to the mixture. Prescribers and consumers must be critical of the ingredients; fragrances can be synthetic, derived from natural sources or plants (essential oils). Many caregivers buy products that claim they contain natural oils; again, most are not advised for use on pediatric skin. Essential oils are extracted and distilled from plants; many solutions have alcohol. Component concentrations are unknown and can cause significant inflammation and irritant reaction. Some, such as peppermint and rosemary, are known to be allergens as well. Claims that a product is “fragrance-free” cause additional confusion. It is not that no fragrance was added to the product; it is a statement that another product was added to take away an originally present scent.
Preservatives. Most products contain some amount of preservative to increase shelf life and impede bacterial growth. Consumers are fearful of additives such as parabens, which has a potential estrogenic effect. Many studies actually do not support this fear. Parabens are large molecules; they do not penetrate skin easily and are very weak endocrine stimulators. Paraben derivatives may be some of the safest preservatives available, as long as the concentration is low and expiration dates are observed. Preservatives are needed because of high, potential contamination risk when double-dipping and tubes coming in contact with the skin are common occurrences. One (1) product aims to bypass the risk of contamination. Touchless Care Zinc Oxide Protectant Spray (3M, St. Paul, Minnesota) is a spray-on mixture of microfine zinc oxide and dimethicone; 1 or 2 pumps is sufficient for a neonate (see Figure 1). Data from studies5 on adults show a 3-fold decrease in bacterial nozzle colonization compared to bottle-based, hands-on application products; an improved economic profile; and favorable use response by caregivers. Pediatric use currently is being investigated.
Zinc. Zinc is an important component of any diaper cream. Occlusives such as dimethicone and petrolatum provide a barrier, hold moisture, and may contribute to the repair of injured skin if components are incorporated into upper SC and stimulate production of intercellular lipids. Zinc oxide has properties (eg, fluid repellent, anti-inflammatory, mild astringent, and antiseptic) that make it an ideal component of a diaper cream. It stabilizes injured cells, halts inflammation, and is soothing, making it a viable additive in burn creams, and products for denuded skin, as well as rectal antihemorrhoidal products that treat burning and irritation. Zinc is a known essential trace element and a cofactor for many cellular enzymes and plays a critical role in nucleic acid metabolism.6 Patients with Acrodermatitis enteropathica, a rare autosomal recessive inherited form of zinc deficiency, have periorificial and acral dermatitis, alopecia, and diarrhea. Wound healing studies6 have shown zinc may promote epithelial healing by enhancing cell division and repair and the structural integrity of dermal and mucosal tissue (by serving as a cofactor in fibroblasts production of collagen and proteins) and through its role in immune function as a mild antiseptic.
Few trials have demonstrated superior efficacy of petrolatum and zinc compared to petrolatum alone. I personally prefer formulations with as few ingredients as possible; the best combination in my opinion includes zinc, dimethicone, and small amount of white petrolatum, with or without karaya or cellulose gum. We use 3 different products for DD in our neonatal intensive care unit and pediatric floors. Two (2) formulations — 1 for prevention and mild DD and 1 for moderate DD — differ in terms of zinc concentration (%) and presence or absence of karaya gum (another effective moisture repellent). For denuded, severe DD, we use a zinc oxide-based hydrophilic paste (Triad, Coloplast Corp, Minneapolis, Minnesota) that is able to dry the area and simultaneously facilitate gentle autolytic debridement.
Fungal DD requires a slightly different preparation that incorporates antifungal products. Two (2) common antifungal preparations contain either nystatin or azoles (eg, miconazole). The products we use has fungal- (incorporating miconazole) and nonfungal options. Candida DD is a result of Candida from normal skin or gut flora penetrating an injured SC barrier. It involves the folds of the groin and thighs, with clusters of reddened papules with sharp borders and satellite lesions (see Figure 2). Some providers may use a visual exam to render a diagnosis or a potassium hydroxide (KOH) prep as a diagnostic test; others simply change to antifungal management if a standard combination of emollient and zinc ointment failed to improve the skin after some time. I recommend ointments that provide good penetration and performing a KOH scraping before the treatment change.
Semipermeable barrier films. Another option in addition to barrier creams (as part of prevention/treatment), these fast-drying, nonalcohol solutions leave a semipermeable barrier film that, once dry, protects the skin from contact with irritants. Many versions are available on the market; our unit uses Cavilon No-Sting Barrier film (3M) on all babies from day 1 including our smallest 23-week preemies.
Skin films also can be incorporated into the “crusting” technique, where a powder is applied first, followed by the film and repeated a few times until an artificial crust is produced to protect an injured surface.
Cyanoacrylate. Products with cyanoacrylate are excellent choices for severe, weepy, exudative dermatitis that needs to be dried. Marathon Liquid Skin Protectant (Medline Industries, Northfield, Illinois) is a non-stinging cyanoacrylate, formulated on small-sized monomers that leave a breathable, flexible, yet durable bond upon polymerization that decreases friction, maceration, and ongoing moisture loss. Cyanoacrylate is different from the previously mentioned films because of its chemical integration into the epidermis and lack of solvent. Cyanoacrylate polymers do not dissolve in water; the resulting film on the skin is designed to be resistant to bodily fluids. However, in my practice, once it is completely dry, I often put a thick layer of petrolatum/combination ointment on top to lessen stool contamination and the need for cleaning (see Figure 3A,B).
A Few Words About Cleansing
For a long time, water and a soft wipe or washcloth have been suggested for neonatal cleaning. These are probably the best choice for very small, preterm neonates. For older children, cleaning stool with pure water may be ineffective and lead to more aggressive rubbing.8 Diaper wipes have bombarded the industry and offer convenience and efficacy, but not without occult dangers such as additives that can lead to allergic dermatitis. The older wipes contained alcohol, preservatives, fragrance, and harsh surfactants. The 2 most common preservatives, methylisothiazolinone and methylchloroisothiazolinone, were important for keeping the wipes moist; they are also among the top 30 allergenic compounds.7 Many of the wipes used today are preservative-free, 99% water, and include a pH-buffering and skin friction protective with a small amount of moisturizer. Since 1940, synthetic detergents or syndets have populated the market. The acidic pH of these products reduces their irritation potential. Modern syndets come infused into soft pre-cut foams, convenient for a small neonatal patient. We use WaterWipes (Water Wipes (USA) Inc, Portsmouth, New Hampshire) in our unit in babies older than 30 weeks and water with soft cloth or foam infused with syndets for babies of less than 30 weeks gestational age.
In conclusion, frequent diaper changes with superabsorbent and/or moisturizer-infused disposable diapers will keep the skin surface drier and protected from moisture. Exposure to air, avoidance of moisture, and preventative product application will minimize DD development. Careful evaluation of wipes, soaps and ointments ingredients is a must! Know the essential components and always remember that putting more products together isn’t always better!