#asktheexpert Doctor my son is 2.5yrs old and recently developed rashes inside his mouth and on his knees. What could be these? He also passes stools after every meal.

A. hi dear A good rule of thumb to remember is that a local rash is most likely caused by skin contact, exposure to certain materials or substances, and sometimes germs, such as diaper rash or an insect bite. A widespread rash is usually associated with a cause that affects the entire body such as measles.