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- Diaper dermatitis is a rash occurring under the covered area of a diaper. It is usually initially a contact dermatitis.
- System(s) affected: skin/exocrine
- Synonym(s): diaper rash; nappy rash; napkin dermatitis
Incontinence is a significant cofactor.
- 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 4–35% in the first 2 years of life. Upward of 75% of infants will have episodes of varying duration and severity in United States.
Etiology and Pathophysiology
- Immature infant skin with histologic, biochemical, functional differences compared to mature skin (1)
- 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.
- 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.
Attention to hygiene during bouts of diarrhea
Commonly Associated Conditions
- Contact (allergic or irritant) dermatitis
- Seborrheic dermatitis
- Atopic dermatitis