Normotension is defined as blood pressure (BP) (systolic, diastolic, or both) that is <90th percentile for the patient’s age, height percentile, and sex. Prehypertension is defined as BP levels ≥90th percentile but <95th percentile. Hypertension is defined as average systolic and/or diastolic BP ≥95th percentile for gender, age, and height on three or more separate occasions (readings).

Labile blood pressure refers to BP (systolic, diastolic, or both) that is sometimes above and sometimes below the 95th percentile and does not result in hypertensive damage to organs. Labile BP is frequently found in teenagers. White coat hypertension is present when elevated BP readings are found in a medical setting with normal BPs measured elsewhere. Masked hypertension is present when the BP is normal or prehypertensive in the office but elevated when measured elsewhere (often confirmed by 24-hour ambulatory BP monitoring).

The prevalence of hypertension in the pediatric population is estimated to be between 1% and 5%. Younger children are more likely to have an underlying cause for hypertension than adolescents and adults. However, primary (essential) hypertension is now seen in children and adolescents and is associated with obesity, metabolic syndrome, and a family history of hypertension.