Brief Answer:
Explained below,

Detailed Answer:
Hello,
Thanks for posting your query,


I have gone through your query and have also viewed the attached pictures,

The usual causes of under eye in young children are due to inadequate sleep and due to frequent allergy. It is common to find darkness under the eye in children suffering from frequent allergy, also termed as "allergic shiner". If your son seems to show symptoms pertaining to allergy, it would be best to get it investigated.

Otherwise, make sure your son gets adequate amount of sleep in the day and also keep a check on the nutrition diet given to your child. If the weight gain is adequate for the age, then rest assured, ensure proper and timely sleep for your child. Keep a routine sleep chart for your child, so that he gets attuned to the daily routine.


You may also use good baby moisturizer for your child to use over the dark circles. It is sure to resolve as the child grows.

I hope this helps,

Please feel free to discuss further, or else kindly close your query and share your positive feedback.

Regards

---

Brief Answer:
Kindly see below,

Detailed Answer:
Hi again,
Thanks for writing back,

Your son will be showing symptoms like frequent running nose, sneezing, frequent rubbing of nose, watering of eyes etc which all are representative of dust allergy or allergy to any pollen or other airborne factors.

I hope this helps,

Regards

---