Hello, Thanks for writing to Health Care magic, I am Dr , Muhammad Ahmad , I have read your question closely, I understand your concern and will be helping you with your health related problem. Yes you should look into this matter closely, usually even if there is family history still high blood pressure in an age this young needs to be looked at. Yes your doctor advised you the right thing to do. Take a diary and start writing his blood pressures three times a day with dates and then take this record to his doctor. In this age there can be a number of causes of blood pressure rise , renal artery stenosis can be one of them hormonal issues can cause it too but first best step to do is making a blood pressure chart. Till tour next visit to doctor reduce salt intake of your son , only if BP is consistently on a higher side. If BP stays on a higher side on checking the record , your doctor might run some more tests on him like catecholamin levels, renal artery doppler, ultra sound abdomen , MRi brain , what ever he deems necessary, to rule out different causes of early onset hypertension. I hope this answered your question, If you have more queries I am happy to answer you. Regards. Dr.Muhammad Ahmad