 [ Symptoms ] my 13 year old has a pulled muscle in his back was told he is not old enough to take muscle relaxants is this true [ Disease ] oral benadryl is safe for younger children but i do not know the exact age when you say under two years old a newborn is under two years old  there are other prescription medications that are often used for eczema in younger children to control the itching so before given benadryl it is best to check with his pediatrician first    someone who knows your child the severity of his eczema and of course his ageweight control itching is extremely important for eczema patients