Nappy rash is a type of dermatitis or inflammatory skin eruption in the nappy area (1). It can occur as early as one week of age, but is most common between 9 and 12 months (2).  It  develops when skin is exposed to prolonged wetness (due to frequent stools and urine, diarrhoea or infrequent changing), increased skin pH caused by urine and faeces,  food sensitivities, yeast infection, bacterial infection, sensitivity to baby wipes and cloth nappies, or dePile of diaper 1tergents (3).


The skin around the genital area and anus will look inflamed, red and moist.  The skin may blister then peel, leaving raw patches (ulcers).  Small ulcers can sometimes form on healthy skin near the area of rash.   The broken skin can become very sore, especially when your baby wees.   This can result in your baby becoming very unsettled, sleeping poorly and waking often due to pain (4).

Skin care

Most cases of nappy rash can be treated successfully.  However a nappy rash that persists for longer than a week needs to be looked at by your doctor or pediatrician.  Start by keeping your baby clean and dry by changing him/her frequently and whenever you notice a wet or filled nappy.  Clean your baby’s bottom using fragrance-free and alcohol-free baby wipes (check the label) or in the bath with warm water and oil cleanse. Pat skin dry.  Apply a thin layer of a certified organic nappy balm to protect the skin from wee or poo and aid healing.  Give your baby some nappy free time in a warm room on a clean towel in the cooler months or on a blanket on the grass in the warmer months to expose his/her bottom to air.

The importance of a dry nappy

Some babies are sensitive to ammonia that develops as their urine breaks down, a condition known as ammonia dermatitis (5).  When urine turns into ammonia it creates a more alkaline environment.  This can be problematic if your baby sits in a full nappy for too long.  Enzymes found in faeces cause the skin to break down (6).  These enzymes thrive in an alkaline environment, so a baby sitting in a full nappy is more prone to skin break down.  Changing your baby’s nappy frequently will help to clear up and prevent a nappy rash.  If you are using cotton nappies, add ½ cup white vinegar to the rinse water when you wash them to help neutralise the ammonia in nappies (7).  Alternatively, make a switch to disposable nappies to keep your baby’s bottom dry and rash free.

Food intake

If skin care doesn’t improve your babies’ nappy rash, it may be due to the pH of your babies’ poo.    Breastfed babies tend to have slightly acidic stools (8). Formula fed babies’ stools tend to be slightly alkaline, so are more prone to nappy rash.  Certain foods may cause your baby’s urine or stools to be more acidic.   An imbalance in either direction can be a problem.  Acidic stools may cause a burn-like rash. Alkaline stools may result in skin breakdown (9).

If your babies’ rash starts shortly after starting solids, you may want to eliminate certain foods to see if the rash goes away.   Keep a food diary to monitor the possible cause of your baby’s nappy rash. Below is a list of aggravating and beneficial foods to consider whilst your baby has nappy rash.

Acid foods to avoid/minimise (10) Protein sensitive’s to avoid (11) Alkaline foods / substances to avoid Beneficial foods
Citrus + juicesTomato



Tart apples, plums, peaches, prunes

Grapes / Raisins




Legumes  / beans


Formula milk madefrom dairy / soy


Ammonia from a wet


Breast milk 


hypoallergenic infant formula



Infant rice cereal

Dry toast

Cooked carrots

white potato


Natural Yoghurt

Apple puree

White grape juice

If the rash doesn’t start to heal, worsens or spreads onto the tummy and buttocks, visit your doctor or pediatrician.

(1)    RCH Dept Dermatology, Pharmacy. (2010). Nappy Rash. Available: Last accessed 17th June 2013.

(2)    Baby Center Australia Medical Advisory Board. (2011). Nappy Rash. Available: Last accessed 17th June 2013.

(3)    et al.

(4)    The Childrens Hospital at Westmead. (2012). Nappy Rash. Available: Last accessed 17th June 2013.


(6)    Ann & Robert H. Lurie. (2013). Diaper Rash. Available: Last accessed 17th June 2013.

(7)    Lisa. (2011). Ammonia and Cloth Diapers. Available: Last accessed 17th June 2013.

(8)    Ogawa K, Ben RA, Pons S, de Paolo MI, Bustos Fernández L.. (1992). Volatile fatty acids, lactic acid, and pH in the stools of breast-fed and bottle-fed infants.. Available: Last accessed 17th June 2013.

(9)    Eastern Region Neonatal Benchmarking Group. (2008). Care of the Nappy Area Guideline. Available: Last accessed 17th June 2013.

(10) Vincent Iannelli, M.D.,. (2013). Infant Q&A – Acidic Baby Foods. Available: Last accessed 17th June, 2013.

(11) Pam Gaulin. (2008). Food Allergies and Diaper Rash. Available: Last accessed 17th June, 2013.