There's a lot for a baby to deal with in the first year of life: adjusting to life outside the cozy confines of the womb, breaking in nervous parents and posing for lots of pictures. And for more than one in three babies, life will also include the irritation and discomfort of diaper rash [source: Murkoff, et al].
It's an alarming sight for parents: buttocks that are red and splotchy, thighs that look rubbed raw, and genital areas that look inflamed. Some children may experience just a mild case, while for others, diaper rash only seems to worsen and linger.
There are different types of diaper rash and different contributing factors. The soreness, rash and chafing that are the hallmarks of diaper rash can be caused by friction, moisture, bacteria, antibiotics and even chemicals. Generally, an initial irritant such as moisture agitates the skin, leaving the weakened skin susceptible to other factors such as bacteria. Fortunately, babies are less prone to diaper rash as they get older and their skin toughens up a bit.
When it comes to fighting the War on Diaper Rash, the best offense is a good defense. As is the case with fruit flies in a kitchen, preventing diaper rash is much easier than getting rid of it. The following five preventive measures will help keep your baby happy, healthy and full of smiles during diaper changes.
Source : https://health.howstuffworks.com/skin-care/problems/baby/5-ways-to-treat-diaper-rash.htm263