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 age/weight. control itching is extremely important for eczema patients.
is it safe to give a child under 2yo benadryl he has eczma and his itching is out of controll used several otc eczma crm