1 – Irritant or Allergic Contact Diaper Dermatitis
This typically presents maximally on the areas of the skin that are most in contact with the irritant or allergen (Figure C). These include the convex areas of the groin but not the hidden folds. This single finding is the most useful clue for distinguishing between contact diaper dermatitis and diaper rash caused by candidal infection—which, in contrast, favors the folds.
The most common irritants in the diaper area are stool and urine. Fragrances and harsh soaps in bathing products can also cause a dermatitis; however, when bathing products are to blame, the dermatitis is usually more generalized, extending beyond the diaper area.
The most common cause of a truly allergic diaper dermatitis is the blue dye—known as disperse blue dye—that is used in many brands of colorful diapers. The folds are almost always completely spared in infants with diaper dye contact dermatitis; also, the shape of this type of rash is a strong clue to the diagnosis. In both dye-allergy dermatitis and the more common irritant dermatitis, the edges of the rash are usually perfectly squared off.
Treatment of both irritant and allergic contact dermatitis includes removal of the offending agent and short-term use (no more than 2 weeks in most cases) of low-potency topical corticosteroid creams. Dye-free diapers are increasingly easy to find and are even sometimes less expensive than their colorful alternatives!