No mom of a baby is a stranger to chapped cheeks and red chins: All that drool typically does a number on the skin around little mouths. But sometimes there's more to those irritated red patches, notes New York City dermatologist Joshua Fox, M.D., and it's called contact dermatitis, a skin allergy that results from contact with a specific irritant and requires professional treatment. Typical causes include latex or rubber in nipples and pacis, nickel used in snaps or earrings (if a baby's ears are pierced), uncovered metal bars on inexpensive strollers, laundry detergents, cleansers, and other skin-care products. If your baby's rash meets any of the criteria below, see your doctor.

* It doesn't diminish when treated with an over-the-counter product such as Aquaphor, A+D ointment, or other creams.

* It's blistering or bleeding.

* It's itchy and uncomfortable to your baby (in contrast, babies are usually oblivious to rashes caused by saliva).

* It's accompanied by a fever.

* Someone else in the family has a similar rash.