What is Diaper Rash?

Nov 11, 2021 | 5 Minute Read

Learn about the characteristics and causes of diaper rash.

What is Diaper Rash?

Diaper rash or diaper dermatitis is irritation of the skin in the diaper area. It is one of the most common skin problems during infancy; about 1 in 4 infants will experience rash at any given time. It can develop as early as the first few days of life and it is usually most frequent around the ages of 9 to 12 months old. Diaper rash mainly occurs when skin has been in prolonged contact with irritants present in poop and urine. Wetness on baby skin for a long period of time can contribute to the onset of diaper rash. Although diaper rash can be mild and recovery can happen within a few days, it can make babies feel uncomfortable and disrupt their sleep. If left untreated, diaper rash can become severe and develop secondary infections requiring prescription treatment.

Characteristics of Diaper Rash:

Diaper rash can be present on baby’s bottom, perianal region, genitals and/or inner thighs.

Diapered Skin Health
  • Slight or Mild Rash: Faint pinkness covering a very small area, skin dryness
  • Moderate Rash: Skin looks red in a large area, can have smaller areas with more intense redness, some areas may have slight swelling and/or small bumps
  • Severe Rash: Intense redness, swelling/bumps in a large area. May develop blisters, sores, and secondary infections.

Dr. Peter Lio, MD, Board Certified Dermatologist and Clinical Assistant Professor of Dermatology & Pediatrics at Northwestern University Feinberg School of Medicine pointed out, “skin redness is less obvious in darker skin tones and may often appear more violet rather than red”.

What are the main causes of diaper rash?

  1. Irritants present in poop
    • Irritants present in poop are the number one cause of diaper rash.
    • Certain components in poop are known to be irritating to skin. In the diaper area, when baby skin is in prolonged contact with poop, these irritants can damage the skin barrier. A damaged skin barrier is not effective at protecting baby from the external environment, allowing penetration of irritants and harmful microorganisms into the inner layers of the skin, leading to skin irritation and the appearance of rash.
    • Irritants from the mixture of poop and urine inside the soiled diaper can increase skin pH. An increase in pH in the diapered area accelerates skin barrier damage. Increased skin pH can also disrupt the skin microbiome balance and cause harmful microorganisms to grow such as Candida albicans (a yeast commonly found as a secondary infection in severe cases of diaper rash).
    • Frequent bowel movements or diarrhea can increase the risk for irritation in the diapered area.
    • Properly formulated baby wipes that are pH balanced can gently and effectively clean poop and urine from baby’s delicate skin while helping maintain a healthy skin pH. Maintaining a healthy skin pH can help mitigate the impact of irritants present in poop. In addition, using diapers specially designed to minimize the contact of poop with the skin also helps to promote skin health.
  2. Prolonged wetness on baby skin
    • Prolonged wetness on baby skin contributes to skin barrier damage and irritation.
    • Did you know that a healthy newborn can urinate up to 24 times per day? This constant exposure has a significant impact on baby’s skin in the diapered area as prolonged wetness makes the skin barrier more permeable to irritants (such as those found in poop and urine) and to harmful microorganisms. Wetness also increases skin pH, disrupts the skin microbiome balance, and makes the skin more easily damaged by friction, increasing the risk for irritation.
    • Changing the diaper frequently and using diapers designed with gentle materials, breathable outer covers, and superabsorbent materials that can quickly absorb fluid and keep it away from the skin can help promote diapered skin health.
  3. Friction (chafing):
    • Baby skin is still developing during the first year of life, making it more susceptible than adult skin to irritation caused by friction or chafing.
    • In the diaper area, if skin stays wet for too long, chafing of the diaper against baby skin or the wiping process when cleaning the skin can lead to irritation as wet skin is more prone to damage by friction.
    • Selecting diapers and wipes made with gentle materials can help minimize friction against the skin, helping to maintain healthy skin.
  4. Allergens and Other Irritants:
    • Some babies can develop a skin rash from direct contact with a specific ingredient or substance in products that may be part of their total hygiene that can be irritating or cause an allergic reaction (irritant or allergic contact dermatitis).
    • Infants with food allergies are more prone to persistent rash.
    • Using diapers and wipes that are hypoallergenic, made from materials specifically selected to be gentle on baby skin, and demonstrated to be a low potential to cause irritation or an allergic reaction on the skin can help minimize the potential for irritation.
  5. Diet and Medications
    • Changes in baby’s diet, food allergies and certain medications (such as antibiotics) can affect poop content, consistency and frequency, increasing the susceptibility for irritation in the diaper area.
When caring for baby’s delicate skin, it is important to understand all the factors that can cause diaper rash and be selective about which diapering products to use. Using a system of diapers and wipes that are designed with baby’s skin health in mind is essential for both cleaning the skin and diapering.

For recommendations on how to provide the best care for baby’s diapered skin, check out the Guide for Maintaining Healthy Diapered Skin.

Karien Rodriguez, PhD Biomedical Engineering
Debbie Ngai, BS Chemical Engineering
Endorsed by Dr. Peter Lio, MD, FAAD, Board Certified Dermatologist; Clinical Assistant Professor of Dermatology & Pediatrics at Northwestern University Feinberg School of Medicine; Founding Director of the Chicago Integrative Eczema Center

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