Dr Ashfaq Ahmad, dispensing medical advice in the Leinster Express.
Nappy rash is very common - most babies will get it at some point. It is not usually a disease, but just an irritation of the skin.
A wet or dirty nappy that has been left touching the skin for too long is the most common cause of nappy rash. This is especially true of children with diarrhoea. Human waste products can turn into ammonia if the nappy isn't changed for a long time.
Waste products eat into the baby's skin, which can then start to sting. A fungal infection due to dampness under the nappy also causes nappy rash. Everybody has fungi on their skin, but it only grows when conditions are right. This has nothing to do with bad hygiene. It is caused by dampness or changes in the skin conditions. A fungal infection can be quite unpleasant for the baby because it can sting the skin, especially when the baby wets or dirties its nappy.
The baby can also get a bacterial infection in the area where the nappy is. This can happen if there has been a small scratch on your baby's skin or if their skin has been weakened by a sustained rash, allowing bacteria to grow easily. The baby's skin will then be red, warm and swollen, and the baby may also get a fever. If your baby has these symptoms, you need to contact your doctor.
The best way to treat ordinary nappy rash is by changing the nappy regularly and also allowing the baby's bottom to get fresh air whenever possible, avoid plastic pants. Apply emollient (E45 cream) after every change.
Use topical nystatin ointment after a nappy change for candida infection, 1% hydrocortison six-hourly for one week if the above measures are ineffective. Once skin has recovered, liberally apply zinc and castor oil barrier cream to prevent recurrence.
If anything else worries you, contact your doctor within 24 hours.