It is called Atopic Dermatitis, this includes infantil dermatitis that effects opposite the elbow and back of knees and other areas.
Mix 8 drops of lavender oil and 8 drops of tea tree oil with 2 teaspoons of vegetable oil.
Use a swab or clean finger and rub some of the mixture on the tongue once a day. Also rub the mixed oils on the eczema at bed time and again in the morning.
You should notice a big improvement in 3 or 4 days, but continue until there is no trace of eczema.
Also add a childrens dosage of zinc supplement to the childs diet. Eczema is common with a zinc deficiency.