<unk>  develops when skin is exposed to prolonged wetness, increased skin pH caused by the combination, and subsequent reactions, of urine and feces, and resulting breakdown of the stratum corneum, or outermost layer of the skin. This may be due to diarrhea, frequent stools, tight<unk> s, overexposure to ammonia, or allergic reactions. In adults, the stratum corneum is composed of 25 to 30 layers of flattened dead keratinocytes, which are continuously shed and replaced from below. These dead cells are interlaid with lipids secreted by the stratum granulosum just underneath, which help to make this layer of the skin a waterproof barrier. The stratum corneum's function is to reduce water loss, repel water, protect deeper layers of the skin from injury, and to repel microbial invasion of the skin. In infants, this layer of the skin is much thinner and more easily disrupted. Urine Cloth<unk>  Although wetness alone has the effect of macerating the skin, softening the stratum corneum, and greatly increasing susceptibility to friction injury, urine has an additional impact on skin integrity because of its effect on skin pH. While studies show that ammonia alone is only a mild skin<unk> , when urea breaks down in the presence of fecal urease it increases pH because ammonia is released, which in turn promotes the activity of fecal enzymes such as protease and lipase. These fecal enzymes increase the skin's hydration and permeability to bile salts which also act as skin<unk> s. There is no detectable difference in rates of<unk>  rash in conventional disposable<unk>  wearers and reusable cloth<unk>  wearers. "Babies wearing superabsorbent disposable<unk> s with a central gelling material have fewer episodes of<unk><unk>  compared with their counterparts wearing cloth<unk> s. However, keep in mind that superabsorbent<unk> s contain dyes that were suspected to cause allergic contact<unk>  (ACD)." Whether wearing cloth or disposable<unk> s they should be changed frequently to prevent<unk>  rash, even if they don't feel wet. To reduce the incidence of<unk>  rash, disposable<unk> s have been engineered to pull moisture away from the baby's skin using synthetic non-biodegradable gel. Today, cloth<unk> s use newly available superabsorbent microfiber cloth placed in a pocket with a layer of light permeable material that contacts the skin. This design serves to pull moisture away from the skin in to the microfiber cloth. This technology is used in most major pocket cloth<unk> s brands today. Diet The interaction between fecal enzyme activity and IDD explains the observation that infant diet and<unk>  rash are linked because fecal enzymes are in turn affected by diet. Breast-fed babies, for example, have a lower incidence of<unk>  rash, possibly because their stools have higher pH and lower enzymatic activity.<unk>  rash is also most likely to be diagnosed in infants 8–12 months old, perhaps in response to an increase in eating solid foods and dietary changes around that age that affect fecal composition. Any time an infant's diet undergoes a significant change (i.e. from breast milk to formula or from milk to solids) there appears to be an increased likelihood of<unk>  rash. The link between feces and IDD is also apparent in the observation that infants are more susceptible to developing<unk>  rash after treating with antibiotics, which affect the intestinal microflora. Also, there is an increased incidence of<unk>  rash in infants who have suffered from diarrhea in the previous 48 hours, which may be because fecal enzymes such as lipase and protease are more active in feces which have passed rapidly through the gastrointestinal tract. Secondary infections The significance of secondary infection in IDD remains controversial. There seems to be no link between presence or absence of IDD and microbial counts. Although apparently healthy infants sometimes culture positive for Candida and other organisms without exhibiting any symptoms, there does seem to be a positive correlation between the severity of the<unk>  rash noted and the likelihood of secondary involvement. A wide variety of infections has been reported, including Staphylococcus aureus, Streptococcus pyogenes, Proteus mirabilis, enterococci and Pseudomonas aeruginosa, but it appears that Candida is the most common opportunistic invader in<unk>  areas.
Irritant diaper dermatitis
Aquagenic pruritus
Psychogenic pruritus
Hydroxyethyl starch-induced pruritus
Exudative hyponychial dermatitis
Blue diaper syndrome
Grocer's itch
Pruritus vulvae