Dermatitis, Diaper



  • Diaper dermatitis is a rash occurring under the covered area of a diaper (named for typical location, not etiology). It is usually initially a contact irritant dermatitis but can be caused by or contributed to by systemic conditions.
  • System(s) affected: skin/exocrine
  • Synonym(s): diaper rash; nappy rash; napkin dermatitis

Geriatric Considerations
Incontinence is a significant cofactor in the elderly population.



  • The most common dermatitis found in infancy
  • Peak incidence: 7 to 12 months of age, then decreases
  • Lower incidence reported in breastfed babies due to lower pH, urease, protease, and lipase activity

Prevalence has been variably reported from 4% to 35% in the first 2 years of life. Upward of 75% of infants will have episodes of varying duration and severity in United States. Severity varies: 58% slight symptoms; 34% moderate; 8% severe. Underreporting contributes to difficulty in determining impact of condition (1).

Etiology and Pathophysiology

  • Immature infant skin with histologic, biochemical, functional differences compared to mature skin (2)
  • Wet skin is central in the development of diaper dermatitis, as prolonged contact with urine or feces results in susceptibility to chemical, enzymatic, and physical injury; wet skin is also penetrated more easily.
  • Fecal proteases and lipases are irritants.
  • Superhydrase urease enzyme found in the stratum corneum liberates ammonia from cutaneous bacteria.
  • Fecal lipase and protease activity is increased by acceleration of GI transit; thus, a higher incidence of irritant diaper dermatitis is observed in babies who have had diarrhea in the previous 48 hours.
  • Once the skin is compromised, secondary infection by Candida albicans is common. 40–75% of diaper rashes that last >3 days are colonized with C. albicans.
  • Bacteria may play a role in diaper dermatitis through reduction of fecal pH and resulting activation of enzymes.
  • Allergy is exceedingly rare as a cause in infants.

Risk Factors

  • Infrequent diaper changes
  • Improper laundering (cloth diapers)
  • Family history of dermatitis
  • Hot, humid weather
  • Recent treatment with oral antibiotics
  • Diarrhea (>3 stools per day increases risk)
  • Dye allergy
  • Eczema may increase risk.

General Prevention

Most effectively managed by prevention including rigorous attention to hygiene

Commonly Associated Conditions

  • Contact (allergic or irritant) dermatitis
  • Seborrheic dermatitis
  • Psoriasis
  • Candidiasis
  • Atopic dermatitis

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