These dark rings under the eyes in children are called 'allergic shiners' and are usually due to an allergic cause, especially nasal allergy. As your son does have a stuffy nose it would be worthwhile having him seen by a paediatrician with an interest in paediatric allergy.
The information provided does not constitute a diagnosis of your condition. You should consult a medical practitioner or other appropriate health care professional for a physical exmanication, diagnosis and formal
advice. Health24 and the expert accept no responsibility or liability for any damage or personal harm you may suffer resulting from making use of this content.