Hello Hemanth, Prominent vascular markings means either Infection or Inflammation in respiratory passages, Allergy or fluid overload. But diagnosis is not made only on the basis of X ray findings. It should be co related with symptoms & signs obtained by physical examination. So, it will be better to consult a Pulmonologist. Appropriate management steps will be taken based on complete history, physical examination & co-relating the findings with investigation reports. And make sure that your son is adequately breast fed & well protected from cold, dust & other allergens. Wish him a good health & speedy recovery. Thanks & take care.