Dr. Bernard Cohen, director of pediatric dermatology at Johns Hopkins Children's Center explains that children can develop toilet seat dermatitis after repeated exposure to residue from harsh cleaning chemicals, or after using a wooden toilet seat which is often coated with paints or varnishes that can irritate the skin.
A study conducted by Dr. Cohen and colleagues found that missed and delayed diagnoses occurred in every case of toilet seat dermatitis before a doctor came upon the correct diagnosis. The researchers suggest that any time a pediatrician sees a child with skin irritation around the buttocks or upper thighs, they should inquire about toilet seats and cleansers used at home and school.
Dr. Cohen explained in a Johns Hopkins news release: