Chapter 2. Diaper Dermatitis
This is one of the most common skin disorders of infancy. Causes are many and must be distinguished in order to prescribe appropriate therapy (Table A). Fortunately, lesion morphology and distribution are diagnostic in the majority of cases.
The most common form of diaper rash is an irritant contact dermatitis caused by prolonged contact of the skin with urine and feces. Once this occurs and the epidermal barrier is broken-down, other substances such as soaps and powders may add to irritation. As most evidence points to feces as the primary culprit, infants with diarrhea are particularly susceptible to irritant diaper dermatitis. The rash is a shiny, red, scaly eruption seen on the convex areas of the perineum, lower abdomen and thighs. It should not be seen in the folds that are relatively protected from exposure. Treatment consists of thorough, gentle cleansing followed by application of lubricants and barrier pastes. All soaps and powders should be avoided. Low-potency topical corticosteroids may speed healing in severe cases.
Allergic contact dermatitis occurs in the diaper area but it is much less common than the other forms of dermatitis. Allergens are commonly found in fragranced baby products and diaper emollients. This rash also primarily involves the convexities and not the folds. When allergy is suspected, treatment consists of mild topical corticosteroids and removal of the offending agent.
Chronic irritant diaper dermatitis is often complicated by secondary infection. The two most common infectious agents include Candida and Staphylococcus aureus. Candidal diaper dermatitis appears as a deep red eruption with red satellite papules and pustules (Figure 1). The rash tends to involve the creases as the fungus thrives in a moist environment. Candidal diaper disease may be associated with oral thrush or candidiasis of other intertriginous areas. The rash responds rapidly to anti-fungal preparations. Secondary staphylococcal infection in the diaper area is easily recognized by finding thin-walled pustules on an erythematous base. The lesions often rupture, leaving behind a collarette of scale. Gram stain and culture confirm the diagnosis. Treatment consists of topical antibiotics.
Seborrheic dermatitis may manifest as persistent diaper dermatitis. The rash will be salmon-colored with greasy, yellow scale and will generally begin in the creases.
There are other less common causes of persistent diaper dermatitis including: psoriasis, zinc deficiency as seen with acrodermatitis enteropathica (Figure 2) and Langerhans’ cell histiocytosis (Figure 3). If a diaper rash does not respond as expected to appropriate therapy, these less common entities should be considered.