Napkin rashes are common, although irritant reactions are much less of a problem with the widespread use of disposable nappies, as they are more absorbent.
Irritant dermatitis, the most common napkin rash, may occur if nappies are not changed frequently enough or if the infant has diarrhoea. However, irritant dermatitis can occur even when the napkin area is cleaned regularly. The rash is due to the irritant effect of urine on the skin of susceptible infants.
Urea-splitting organisms in faeces increase the alkalinity and likelihood of a rash. The irritant eruption affects the convex surfaces of the buttocks, perineal region, lower abdomen and top of thighs. Characteristically, the flexures are spared, which differentiates it from other causes of napkin rash.
The rash is erythematous and may have a scalded appearance. More severe forms are associated with erosions and ulcer formation. Mild cases respond to the use of a protective emollient, whereas more severe cases may require mild topical corticosteroids. While leaving the child without a napkin will accelerate resolution, it is rarely practical at home. Candida infection may cause and often complicates napkin rashes. The rash is erythematous, includes the skin flexures and there may be satellite lesions.
Treatment is with a topical antifungal agent.