Pigmentation disorders are common in children below 6 months of age. Generally we find a hypo pigmented patch on the chest and mid auxiliary line and a hypo and hyper pigmented mixed patch on their right flank and cafe-au-lait spots on their buttocks. When such pigmentation is observed you need to think whether this pigmentation is by birth or whether it has started at 6 month. If the pigmentation is by birth then it is a congenital disorder that is inherited from mother to the child. In case of congenital disorder it can be nevus anemicus or nevus depegmentosis and tuberous sclerosis. Nevus depigmentosis and nevus anemicus is generally referred to as birth mark and treatment cannot be done in these conditions.
Tuberous sclerosis is a condition where the similar patches are seen as in nevous anemicus and nevous depigmentosis. In case of tuberous sclerosis there are chances that in future the child might develop epileptic seizures. Epilepsy is a condition where the nervous system is mainly affected and the person has seizures and often involves convulsions or loss of consciousness.
In cases when the patch has occurred in later stages of life and is not by birth, then that is referred to as post-inflammatory condition that leaves a post inflammatory hypo pigmented patch or post inflammatory hyper pigmented patch. Cafe-au-lait spots are in the form of large spots or patches that can also be seen in few children.
Von Recklinghausen disease or neurofibromatosis also shows similar kind of patches and in this disease also you may find cafe-au-lait spots. There are some other symptoms that you may find in the later stages like nodules coming up along the cores of the nerves. Nodules are very painful.
Whenever the pigmentation is seen on the body you need to first recognise whether the symptoms are by birth or it has appeared in later stages. You need to consult dermatologist in such conditions who can diagnose and treat these patches.