What causes adult diaper rash?

Also known as nappy rash, the diaper dermatitis is a localised skin redness caused by the dilation of blood vessels due to inflammation. In addition to redness, it manifests as increased skin sensitivity, sometimes accompanied by itching and small blisters. As the name suggests, diaper dermatitis appears on the buttocks, thighs, and groin. It is very common and is usually associated with infants. According to a study conducted by HASANPOOR-AZGHADI and his team, between 7 to 35% of newborns are affected by diaper dermatitis. However, although less often mentioned, due to modesty or embarrassment, diaper dermatitis can also affect adults.

One of the primary triggers of nappy rash is the prolonged skin contact with moisture, due to perspiration, wearing absorbent protections, or inadequate hygiene. Extended maceration impairs the hydrolipidic film, this thin layer of lipids and water that plays a crucial role in protecting the skin against external aggressions. When this barrier is compromised, the skin becomes more permeable to irritants and pathogens. This skin fragility can be exacerbated by the use of products unsuitable for the sensitive buttock area. Soaps that are too detergent or scented wipes can indeed contribute to destabilising the skin microbiota and drying out the skin, which can lead to irritation.

Additional factors such as friction, particularly in individuals who wear tight underwear or urinary pads, can contribute to skin irritation. Moreover, in cases of urinary or faecal incontinence, the skin is frequently exposed to irritating chemical substances. Ammonia, which is produced from the breakdown of urine, disrupts the skin's pH, which is normally slightly acidic, around 5.5. This disrupts the skin's microbiota and weakens the skin's natural defences against pathogens, particularly against Candida albicans, a fungus that thrives in warm, moist environments and can cause red patches on the skin and a burning sensation. Furthermore, digestive enzymes present in faeces, such as lipase and protease, have a proteolytic effect and destroy the skin's protein structures, exacerbating irritation and lesions.

Adult diaper rash is caused by a combination of irritative, mechanical, and infectious factors.