A 30-year-old Caucasian female brings her 3-week-old son into the clinic with a skin condition on both feet. The mother reports that the pregnancy was uncomplicated. She says the baby was born full-term with a normal birth weight of 7.2 pounds and no problems noted. The mother also says she was healthy before and during the pregnancy, and that she is not taking any prescription medications or other drugs. She has been taking regular perinatal vitamins and minerals, including vitamin C and E, as directed by her personal obstetrician.