There are however a number of pathological causes of toe walking that need to be investigated or and followed up:

Habit – kids are short and like to be taller, so walk on their toes. All other causes need to be excluded before this is left alone

Tight calf muscles – these may need stretching exercises or in extreme cases, surgical lengthening

Cerebral palsy – this is the most common cause of toes walking and is due to the spasticity of the muscles

Autism spectrum – there is a high correlation between toes walking and autism, but the mechanism of the link is not clear

Paralytic muscle diseases, such as some of the muscle dystrophies can cause toes walking

In almost all cases, physical therapy is warranted for calf muscle stretching. Sometime ankle foot orthoses are used to hold the foot in a dorsiflexed position.

For more:

Toe Walking (Podiatry Arena)

Toe Walking (Podiatry Online TV)