This group of inflammatory conditions in the groin area is the most common dermatologic problem of infancy. Overhydration of skin, skin-on-skin friction, presence of urine, feces, and microorganisms all play a role in the development of diaper dermatitis. Less commonly, diaper rash can be a symptom of nutritional deficiency or more severe systemic illness (e.g., Kawasaki disease, histiocytosis).
Enzymes and alterations in pH in stool and urine break down skin. Friction from skin-on-skin movement leads to irritation. Once skin integrity is interrupted from overhydration and irritation, fungi and bacteria, and occasionally viruses (such as HSV) may invade skin, leading to infection.
Contact or irritant diaper dermatitis appears as redness and scaling of convex areas of skin (“mountain peaks”) that come into contact with the diaper that usually spares skin folds.20 Candidal diaper dermatitis features beefy erythema in intertriginous areas (“valleys”) with papular “satellite” lesions. Infants may have oral thrush present.
Bacterial diaper dermatitis is typified by the presence of bullae or impetiginous lesions (honey crust). In folliculitis, small red papules and pustules are present on the buttocks, thighs and low abdomen HSV can occur in the diaper area, with vesicles or bullae noted during first few weeks of life progressing to punched-out blisters. A severe form of diaper dermatitis called Jacquet dermatitis features severe erosions with punched-out lesions.
The following actions can help prevent diaper rash: frequent changing of diapers (q3 to 4 hours or ASAP when stool or urine is present), using barrier cream skin protection (e.g., zinc oxide, petrolatum), using nonocclusive diapers, using superabsorbent diapers, and avoiding cloth diapers and scented wipes.
For contact (irritant) dermatitis a topical barrier paste, ointment, or cream (e.g., zinc oxide, petrolatum, lanolin) should be liberally applied every diaper change. For severe cases, a low-potency steroid cream (hydrocortisone 1%) can be applied topically BID for maximum of 2 weeks. Stomahesive powder is reserved for severe cases refractory to steroids and barrier creams. Cornstarch powder applied topically to the diaper area (and taking special care to avoid the infant's face where aspiration may occur) daily can help reduce friction on skin. This is especially useful for contact dermatitis associated with prolonged wetness. Irritant diaper dermatitis present for >3 days usually has a component of Candida infection, even if the typical candidal appearance is not yet present. Treat these cases with an antifungal cream.21
For fungal dermatitis a topical antifungal (miconazole, clotrimazole, nystatin creams) should be applied directly to skin every diaper change until clear for 7 days. Some advocate additional application of a layer of a barrier cream. For bacterial infections topical mupirocin 2% cream applied TID can be used until clear for 7 days. Mupirocin has antifungal properties, so if you are treating a presumed bacterial infection, it may obviate the need to also apply an antifungal cream.22
Clinical appearance alone is usually sufficient to make the diagnosis. If diagnosis is in question, a skin scraping will show pseudohyphae when potassium hydroxide (KOH) preparation is done in cases of Candida diaper dermatitis. Culture of bullae or lesions may yield definitive diagnosis In rare cases of refractory dermatitis with other systemic symptoms (e.g., failure to thrive in nutritional deficiencies, hepatosplenomegaly, and chronic otorrhea in histiocytosis) other studies including nutrient levels or biopsies are warranted.