Napkin dermatitis (commonly called nappy rash) is defined as an irritant contact dermatitis caused by the interaction of several factors. In particular, it involves the prolonged contact of the skin with urine and faeces, which makes the skin more prone to disruption through friction with the napkin.1 Napkin dermatitis is the most common dermatological condition in infants, and it is estimated that infants have a one in four chance of developing the condition.2 The peak incidence for napkin dermatitis is 6-18 months of age, both sexes are equally affected, and there is no ethnic variation.3

Symptoms

Napkin dermatitis can be defined as mild, moderate or severe.4 Mild napkin dermatitis is defined as a pink eruption, with scattered papules on the area covered by a nappy, while scaling and/or dryness may be present.5 Moderate napkin dermatitis is defined as moderate to severe inflammation covering an area of greater than 10% of the area covered by a nappy, with or without papules, oedema or ulceration. Severe nappy rash is secondarily infected with Candida albicans or staphylococcus aureus or other bacteria.

Differential diagnosis

Always consider differential diagnosis especially in moderate to severe napkin dermatitis that is not obviously infected. Differential diagnoses include seborrhoeic dermatitis (salmon pink patches in flexures, scalp affected yellow crusts), atopic eczema (conversely nappy area is often spared), psoriasis (well circumcised shiny red plaque, family history), scabies (intense pruritus) and rarely zinc deficiency called acrodermatitis enteropathica (severe inflammation, resistant to treatment) or cellulitis.6

bjfm napkin rash fig1

Causes

Immature infant skin barrier

The skin has several important functions, including protection, preventing the penetration of irritants and allergies and preventing infection – all by maintaining a stable water content to maintain an effective skin barrier. Raised skin pH in infants results in poor skin barrier function allowing for percutaneous invasion by pathogens. In infants without atopic eczema, this is due to the development of the acid mantle of the stratum corneum, which optimally should be pH 5.5).7 Infants have an immature skin barrier compared to adults, which is not fully developed until 12 months of age, the epidermis is thinner and the distribution of water transport immature, so the skin barrier is more prone to damage.8 This, combined with with environment adverse effects such as soaps and detergents, contributes to the development of napkin dermatitis.

Primary and secondary factors

Primary factors that contribute to napkin dermatitis include maceration (softening and breaking down of skin due to prolonged moisture), friction, urine, faeces/ diarrhoea and poor or misguided skin care.

Excessive wetness interferes with the skin barrier and makes it more permeable to irritant substances and more fragile, making the skin more susceptible to damage by friction. Prolonged exposure, with moisture staying in contact with the skin, produces erythema. Urine is the main cause of moisture, and infants pass urine more than 20 times in 24 hours. The critical factor is the ability of urine to increase epidermal penetration and urinary pH. Therefore, the more alkaline the urinary pH, the more likely the infant is to develop an irritant dermatitis, especially when it interacts with faeces, (faecal enzymes are harsh skin irritants) and ureases (produced by skin bacteria) also raise skin pH, especially in cow’s milk formula-fed infants.9 Soap and harsh surfactants, for example sodium lauryl sulphate, are an important environmental factor in napkin dermatitis. Soap can raise the skin pH to above 8.0, which in turn facilitates skin barrier deterioration.10 Damp nappies cause irritation due to ammonia, which is an alkaline irritant.

Secondary factors contributing to napkin dermatitis include microorganisms, the use of antibiotics and, rarely, developmental disorders of the urinary tract. Bacteria appears to have a limited role in napkin dermatitis and evidence points to Candida albicans, identified in faeces, as a causative fungal infection for severe napkin dermatitis (often termed napkin candidiasis). Maceration of the skin is a prerequisite for Candida albicans, due to a damaged skin barrier (candida infections are also linked to broad-spectrum antibiotics), so this organism is likely to be established in napkin dermatitis. In the more severe form it becomes napkin candidiasis, where symptoms include intense erythema spreading into skin folds and a scalloped
margin with scaling present, which requires anti-fungal treatment.9

Treatment

NICE guidance4 provides an evidence-based approach to treating napkin dermatitis. Skin care, as described in the parental advice section below, is essential for all forms of napkin dermatitis and as a preventative measure and treatment for mild napkin dermatitis, including washing, choice of nappy and barrier preparations).

Moderate napkin dermatitis causing the infant discomfort should be additionally treated with 0.5% or 1% hydrocortisone cream once a day for 7 days until symptoms settle.4 In severe napkin dermatitis, fungal or bacterial infection is generally present and a diagnosis of the infection needs to be made. Fungal infections should be treated with a topical imidazole. NICE (2013) recommends the following regimens depending on choice of imidiazole:

  • Clotrimazole 1% cream: apply 2–3 times daily. Continue for at least 2 weeks after the affected area
    has healed
  • Econazole 1% cream: apply twice daily. Continue application until all skin lesions are healed
  • Miconazole 2% cream: apply twice daily. Continue for 10 days after the affected area has healed.

If severe napkin dermatitis is complicated by bacterial infection, prescribe an oral flucloxacillin for 7 days (oral erythromycin or clarithromycin for 7 days are alternatives for children who are allergic to penicillin).4 A mild topical steroid should also be prescribed alongside anti-fungal or antibiotic treatment. These should be applied at a different time to application for anti-fungal creams. Combined topical antifungal/ steroid preparations are not recommended, as the dilution of topical steroid in the formulation will not effectively treat severe inflammation. If treatment fails, a swab should be taken to check for bacterial or fungal infection, and the appropriate antibiotic. If napkin dermatitis does not respond the infant should be referred for specialist advice.4

Treatments not recommended include ‘natural creams’ marketed for nappy rash, for example those that contain marigold, tea tree or honey, as the evidence base is low. Vitamin A creams are also not recommended. One trial compared vitamin A cream with placebo in 114 infants and found no differences between the two groups.11 Talcum powder should be avoided as it causes friction and will further irritate the skin and cause clogging and affect nappy absorption.

Parental advice

Prevention of napkin dermatitis is key, so all health care professionals should be able to give parental advice on good nappy care. Infant skin care is crucial to protect the skin from irritants and prevent napkin dermatitis in the first year. Maintaining a constant skin pH of around 5.5 is an important factor, so infants should be washed with an emollient soap-free, fragrance-free liquid cleanser, or warm water alone.12 Any potential skin irritants or substances that dry the skin or increase skin pH (which increases colonisation of microorganisms), should be avoided, including soaps, detergents and surfactants (bubble baths), any perfumed products and alcohol and fragranced napkin wipes. Bathing more than twice a day should also be avoided.4

Prevention of napkin dermatitis should include good-quality super absorbent nappies (with absorbent gel-matrix materials) and the application of a barrier preparation at every napkin change.1 There is a range of barrier cream preparations available as ointments and pastes formulated with ingredients that form a film and which protects skin from exposure to moisture.

Conclusion

Mild and moderate napkin dermatitis should be managed with good skin care and barrier preparations and, if required, mild topical steroids for 7 days. Differential diagnosis should be considered in severe napkin dermatitis that does not respond to treatment, or refer to dermatology or paediatrics.

bjfm napkin rash fig2

References

1. Atherton D, Mills K. Midwives 2004;7(7): 288-90
2. Bikowski J. Practical Dermatology for Paediatrics. 2011. 16-19.
3. Atherton, DJ. European Academy of Dermatology and Venereology. 15. Suplt 1:1-4.
4. NICE (2013) Nappy rash. CKS. Available at: https://cks.nice.org.uk/nappy-rash [Last accessed February 2018]
5. Odio MR, O’Connor RJ, Sarbaugh F, Baldwin, S. Dermatology. 2000: 200(3): 238-243.
6. Oakley A. Napkin Dermatitis. DermNet NZ. Available at https://www.dermnetnz.org/topics/napkin-dermatitis/ [Last accessed February 2018]
7. Ness M, Davis D, Carey W. International Journal of Dermatology. 2013. 52: 14-22
8. Nikolovski J, Stamatas GN, Kollias N, Wiegnand BC. Journal of Investigative Dermatology. 2008. 128(7):1728-36.
9. Paige DG, Gennery AR, Cant AJ. The Neonate. In Burns T, Breathnach S, Cox N, Griffiths C (eds). Rook’s Textbook of Dermatology – 8th Edition. 1(17): 1-85. Oxford. Wiley-Blackwell
10. Danby SG, Cork MJ. The skin barrier in atopic dermatitis. In Irvine A, Hoeger P and Yan A (eds) Harper’s Textbook of Paediatric Dermatology (3rd edition 2011); 1(2):317-335. Oxford. Wiley-Blackwell.
11. Davies MW, Dore AJ, Perissinotto KL. Vitamin A creams and lotions for nappy (diaper) rash 2005. Available at: http://www.
cochrane.org/CD004300/SKIN_vitamin-a-creams-and-lotions-for-nappy-diaper-rash [Last accessed February 18]
12. Lavender T, Bedwell C, Roberts S et al. Journal of Obstetric Gynecological and Neonatal Nursing. 2013. 42(2):203-214.

 

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