Pediatric hypertension shows up in maybe 3–4% of kids, but most get missed because people measure BP randomly or don't think kids get high blood pressure in the first place. The 2017 AAP guidelines changed how we diagnose it, and actually doing it right prevents both false alarms and missed cases.
What Changed in 2017
The old approach used flat percentile cutoffs. Now we use age, sex, AND height because a tall 10-year-old's "normal" is different from a short 10-year-old's. Same absolute BP number can be 87th percentile in one kid and 95th in another.
And measurement actually matters. Sit them down for 5 minutes, use a properly sized cuff (bladder wrapping 80% of the arm), and don't overreact to a single reading. One elevated BP doesn't make the diagnosis.
The Three Stages
Normal (<90th percentile)
For children aged 1–13, normal BP is below the 90th percentile for age, sex, and height. For adolescents ≥13, normal is <120/80 mmHg.
Elevated BP (≥90th to <95th percentile, or 120/80 to <130/80 in adolescents ≥13)
This is your chance to intervene early. Diet, exercise, weight management if needed, and sodium restriction. Many kids normalize with lifestyle changes alone. Repeat the BP across multiple visits before making a diagnosis, as office anxiety is real.
Stage 1 Hypertension (≥95th percentile to <95th percentile + 12 mmHg, or 130/80 to 139/89 in adolescents ≥13)
Established hypertension. Work them up for secondary causes: kidney disease, coarctation, endocrine disorders. Try lifestyle changes first. Start medications if there is end-organ damage, concurrent diabetes, or no improvement after 6 months of lifestyle modification.
Stage 2 Hypertension (≥95th percentile + 12 mmHg, or ≥140/90 in adolescents ≥13)
This usually requires medications alongside a secondary workup. Refer to nephrology or cardiology.
Use the AAP BP 2017 calculator to get the percentile. Heights matter; don't skip it.
When to Screen
Start at age 3 during well visits. Before age 3, only screen kids with risk factors: premature birth, kidney disease, heart disease, or strong family history of early hypertension.
Teenagers with obesity, diabetes, CKD, or worrying family history need more frequent checks.
Height Adjustment Is Critical
Two kids of the same age with identical BP readings can be in different categories if one is tall and one is short. This may seem pedantic until you realize you're either over-treating a normal tall kid or missing hypertension in a short one.
The AAP BP Full calculator does this for you. Use it.
Ambulatory BP Monitoring
Here's where ABPM (24-hour monitor) becomes your friend: maybe 25–40% of kids flagged for hypertension in the office actually have white coat syndrome, they're nervous at the doctor, BP goes up, and it's normal everywhere else. ABPM tells you which is which.
It also shows you nocturnal dipping (blood pressure should drop at night, if it doesn't, that's prognostic), BP variability, and how your treatment is actually working. Increasingly, specialists recommend ABPM as part of the initial workup for stage 1 or stage 2, not as an afterthought.
Secondary Causes
About 5–10% of hypertensive kids have something fixable: kidney disease, renal artery stenosis, coarctation, thyroid stuff, medication effects. So actually look, check femoral pulses, get renal ultrasound, screen for end-organ damage with echo (left ventricular hypertrophy) and urine (proteinuria).
Making It Stick
Get your team trained on proper BP technique. Right cuff size, 5-minute rest, no talking, averaged across visits. Build the calculator into your visit flow. Refer early if it's stage 2, you find secondary causes, or lifestyle stuff isn't working.
2017 AAP guidelines with proper height-based percentiles work. Do the measurement right, use ABPM when you're unsure, look for secondary causes, and don't medicate until you're sure it's real.