Nappy rash Basics

Help! My baby has a nappy rash, I have tried all the bum creams and it just does not get any better! It looks so sore!”

Does that sound familiar? Nappy rash, also called “Diaper Dermatitis” or “Irritant contact dermatitis” is one of the most common issues in infancy affecting one in 3 or even every second baby. Nappy rash can develop in the first few weeks of life, but gets more common once babies start to eat – it is most common in babies between 9-12months of age. Breastfed babies have a lower risk to develop nappy rash as their stools have a lower pH. Disposable nappies also cause less nappy rash than traditional cloth nappies (studies are not yet done on newer, highly absorbent cloth nappies).

“Cultivate your sense of humour. On life’s journey from nappy rash to denture adhesive, humour is a great pain reliever.” – James Simpson

Allow me to explain some of the physiology of how a typical nappy rash develops, then you will be able to understand the how and why of the treatment:

  • When moisture (aka urine) is “sealed in” on the skin (not breathable), it leads to overhydration of the skin which breaks down the outside barrier of the skin.
  • There is constant friction between the nappy and the skin of the buttocks, genitalia, abdomen and thighs, and this leads to chafing (areas of red, irritated skin). This allows more irritants, allergens and microbes to enter the body and cause reactions.
  • The more acid pH of normal skin is an important part of the skin’s defence system. Prolonged exposure to urine and stool leads to an increase in the skin pH due to the release of ammonium (becomes more alkaline), resulting in changes of the microbiome, activation of enzymes and breakdown of the skin barrier. If the pH of the skin gets too acidic (e.g. with diahroea or when food/drink is acidic e.g. orange juice or when teething) the skin barrier will also be affected.
  • When the skin barrier does not function well, there is a higher risk of infection and inflammation. Other conditions that also disrupt the skin barrier thus also increase the risk for nappy rash (e.g. atopic dermatitis (eczema) and seborrheic dermatitis).

How do you know if your child has a typical nappy rash (irritant contact dermatitis)?

  • The skin of the buttocks and other areas covered by the nappy looks red and shiny. There might be some areas with blisters or ulcers. The area inside the skinfolds of the legs and genitalia are usually spared. With appropriate treatment (as discussed below) it usually improves within 3 days.

If the rash looks drastically different, or does not improve with appropriate treatment, it is better to see your health care worker sooner rather than later to help you with a specific diagnosis. They will examine the rash and might take swabs to identify the specific cause so that your baby can get the right treatment.

Here are some examples of other causes that can lead to a red, painful bum:

  • Candida nappy rash: The most common reason for a nappy rash that does not respond to bum creams. It usually starts out as a typical nappy rash that then becomes infected with Candida (a yeast). The skin is a deep red with small white scales and satellite patches of red dots outside the rash area. The skin folds are also affected. Treatment: you will need to apply an anti-fungal ointment such as Nystatin or Clotrimazole with every nappy change.
  • Infected contact dermatitis: Usually a secondary infection caused by bacteria, viruses and even parasites, can present with ulcers or blisters. Treatment: Topical or oral antibiotics, antivirals or antiparasitic treatment.
  • Allergic dermatitis: Allergic reaction to washing powder / chemicals in disposable nappies / chemicals in wet wipes that starts within one week of using a new product. Allergic reaction can continue up to 2 weeks after stopping the product. Treatment: Remove allergen, use low-dose steroid ointment to calm inflammation.
  • Diarrhoea and antibiotic use: Frequent loose stools and the use of antibiotics both play a role to change the pH of the skin and damage the skin barrier. Treatment: General management as discussed below.
  • Seborrheic dermatitis: This is due to inflammation of the sebum-producing glands and is common in infants. The skin is red with yellowish, scaly, oily patches. The skinfolds are also affected. It can affect the face (especially the eyebrows), scalp (cradle cap) and other skinfolds of the arms and neck at the same time.  Treatment: Ketoconazole shampoo (Kez shampoo) improves cradle cap and other areas of the rash.
  • Psoriasis: Another chronic skin condition that can affect any area of the body with persistent red scaly patches with well-defined borders. Luckily rare, more complex to treat.
  • Micronutrient deficiencies: Vitamins and minerals play a big part in the maintenance of an intact skin barrier. Zinc deficiency and biotin (Vitamin B) deficiency can cause or aggravate nappy rashes. Supplements should be given together with general management as discussed below.

There are other rare skin and systemic diseases that can also cause or worsen nappy rashes, but because they are so rare and specialized they will only be considered after the above mentioned causes are excluded.

General Management:

Congratulations, you have just completed the first step of treating your baby’s nappy rash: Education. 😉 We use an ABC approach for the general management of nappy rashes in babies. In summary you want to support the skin barrier, maintain dryness, reduce friction and limit exposure to irritants.

The following tips will help to prevent nappy rashes by maintaining a healthy skin barrier, but are also vital to follow when you are treating a nappy rash:

A – Air

It is important to give those cute bums some air. Use a towel or a linen-saver to minimize messes and allow your little one to have some time during the day without a nappy on. Try to combine it with tummy time / give them some nappy-free time before bath time. Also make sure that your nappy is breathable, avoid using plastic pants over cloth nappies.

B – Barrier

Barrier creams (or emollients) can protect the nappy-area by coating the skin surface to prevent exposure to moisture and irritants. Depending on the formulation it can also provide lipids to assist in repair of the outer layers of the skin. It should be applied in a thin layer in the nappy area so that it does not totally occlude and trap moisture in the skinfolds.

If the skin is healthy, you need to apply an emollient at least twice a week to support the skin barrier. If you use it for treatment of a nappy rash it needs to be applied with every nappy change. If you need to use antifungals or steroid ointments, apply those first and cover it with the barrier cream.

Zinc oxide is a very good ingredient to look for in a barrier cream as it also assists in the healing of the skin. Petroleum jelly, lanolin and panthenol are also ingredients that create a barrier. E.g Bennet’s bum crème, Bepanthen, Sudocrem, Antipeol. 

Maizena (corn starch) can also be used to absorb any redundant moisture. Apply generously on a dry bum in the place of baby powder.

“You are my hiding place; you will protect me from trouble and surround me with songs of deliverance” Psalm 32:7

C – Cleansing

It is important to remove the irritants from the skin gently to protect the skin barrier. Use water and cotton balls or a soft cloth, or wet wipes to clean off the urine and stools from the skin. Studies show that wet wipes are safe to use if they do not have potential irritants such as alcohol, fragrances, soap, or harsh detergents such as sodium lauryl sulphate.

D – Diaper

Disposable nappies are highly absorbent and are engineered to reduce irritants, but contain a lot of chemicals to achieve this. It uses materials that are breathable and stretchy to assist in comfort of wear. Modern cloth nappies are also more absorbent and designed to have a better fit with the advantage of not exposing your little one to chemicals. Be careful to rinse cloth nappies thoroughly to prevent the washing soap from becoming an irritant.

Baseline is to choose a nappy that fits your baby comfortably to reduce friction. Change the nappy frequently to ensure that baby’s bum stays happy and dry (2-3hourly if they already have a rash).

E – Education

Done! 😉

Other ointments that might be prescribed by your health care worker in a nappy rash that does not respond to the above treatment includes:

  • Mild topical steroid such as Hydrocortisone 1% that can be applied to inflamed skin once or twice daily for a maximum of 1 week. Strong steroid creams should not be used in the nappy area as there will be too much of the steroid absorbed with local and systemic side effects.
  • Topical antifungal cream (eg nystatin, clotrimazole) applied with each nappy change

Please let me know which tips you have to help your baby when they have a nappy rash!


  1. Blume-Peytayi U, Kanti V; “Prevention and treatment of diaper dermatitis”; Pediatric Dermatology; Volume 35, Issue S1; pg s19-s23
  2. Cohen B; “Differential Diagnosis of Diaper Dermatitis”; Clinical Pediatrics; Vol 56, Issue 5_suppl, 2017
  3. Van Gysel D; “Infections and skin diseases mimicking diaper dermatitis”; International Journal of Dermatology; Vol 55 Issue S1; pg 10-13

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