What causes nappy rash?

The main cause of nappy rash is wetness results from contact with wee and poo in a nappy. Newborns wee are often runny poos Viral Rash on Babies

Even the most effective nappy leaves some moisture on a baby's soft new skin. This makes it harder for your baby's skin to work as a barrier, making it more likely that her skin will become irritated. 

A baby left in a dirty nappy for too long is more likely to develop nappy rash. However, it can also strike the bottoms of babies with particularly sensitive skin, even if they have frequent, fresh nappies. 

The reaction between wee and poo compressed together in a nappy can be particularly bad for your baby's skin. A bout of diarrhea can make your baby more prone to nappy rash. That's because poo is spread over a wider area, and is wetter than usual. 

Occasionally, other things can cause nappy rash. Your baby may have an allergic reaction to a product that has touched her skin. This is called allergic dermatitis, but it's rare for a baby to get it. 

Allergic dermatitis could be triggered by a different brand of nappy, or a new cleanser or baby wipe. Sometimes it's obvious what the cause is, as the rash develops immediately after you've changed to a new product.