SymptomHormones & metabolism
Excessive Growth (Overgrowth)
Excessive growth means a child growing much faster or taller than expected for their age and family, an adult whose hands, feet or face keep enlarging, or one part of the body growing larger than the rest. Most tall children simply have tall parents. Medical causes include early puberty, excess growth hormone (gigantism or acromegaly), genetic conditions such as Marfan, Klinefelter and Sotos syndromes, and an overactive thyroid. A child crossing growth chart lines upward should be checked.
Also called: Overgrowth, tall stature, accelerated growth, abnormal growth, gigantism, hemihypertrophy (one side)
At a glance
- What it is
- Growth well above the expected rate or size for age and family, either overall or in one body part.
- Most common reason
- Familial tall stature, where tall parents have tall, healthy children.
- Medical causes
- Early puberty, excess growth hormone, thyroid overactivity, genetic syndromes, obesity in childhood.
- Warning signs
- Crossing growth lines upward, puberty before 8 (girls) or 9 (boys), headaches or vision changes, enlarging hands or feet in adults.
- Diagnosis
- Growth charts, bone age X-ray, hormone blood tests, genetic tests and pituitary MRI.
When to get help
See a doctor within a day or two
- A child or adult with rapid growth plus severe or worsening headaches, vomiting or loss of side vision (possible pituitary tumor)
- Sudden chest or back pain in someone who is very tall with long limbs and flexible joints (possible aortic dissection in Marfan syndrome)
Book a routine appointment
- A child whose height moves up across two or more major lines on the growth chart
- Signs of puberty (breasts, pubic hair, testicular enlargement, body odor with a growth spurt) before age 8 in girls or 9 in boys
- An adult whose ring, shoe or hat size keeps increasing, or whose facial features are coarsening
- One arm, leg or side of the face that is noticeably larger than the other
- A very tall child with long fingers, loose joints, lens problems or a sunken or protruding breastbone
Usually safe to manage at home
- A tall, healthy child with tall parents who has grown steadily along the same growth line
What counts as excessive growth
Children grow at a predictable rate and usually track along one line (centile) on a growth chart. Doctors look at three things:
- Height compared with peers: above the 97th to 98th centile, or more than 2 standard deviations above average.
- Height compared with parents: a child's expected adult height is estimated from the parents' heights (mid-parental height). A child far above that range needs a look.
- Growth speed (velocity): a child who keeps accelerating and crossing centile lines upward is more concerning than one who has always been tall.
In adults, the long bones cannot grow once the growth plates close, but excess growth hormone still enlarges the hands, feet, jaw, nose, tongue and internal organs.
Common, harmless causes
Familial tall stature
The most common cause. The child is tall from early on, grows at a normal speed, enters puberty at the usual age, and is expected to finish within the range predicted by the parents' heights.
Constitutional advanced growth
Some children grow faster in early childhood and enter puberty a little early, but finish at a normal adult height.
Childhood obesity
Children with excess weight often grow taller and enter puberty earlier than their peers. Their final adult height is usually normal.
Medical causes of excessive growth
Early (precocious) puberty
Sex hormones cause a growth spurt. When puberty starts too early, a child grows fast and is tall for age, but the growth plates close early, so adult height can end up shorter. See precocious puberty. Causes include early activation of the brain's puberty signal (often no cause is found in girls), brain lesions, congenital adrenal hyperplasia, ovarian or testicular tumors, McCune-Albright syndrome and exposure to sex hormone creams.
Excess growth hormone
Usually from a benign pituitary adenoma.
- Gigantism: before growth plates close, causing extreme height.
- Acromegaly: in adults, causing enlarged hands and feet, coarse facial features, a protruding jaw, wider tooth gaps, deep voice, sweating, joint pain, sleep apnea, high blood pressure and diabetes. It develops so slowly that diagnosis often takes years. Comparing old photographs helps.
Hyperthyroidism
An overactive thyroid speeds up growth and bone maturation in children, with weight loss, a fast heart rate, heat intolerance and restlessness. See hyperthyroidism.
Genetic conditions with tall stature
| Condition | Key features |
|---|---|
| Marfan syndrome | Tall and thin, long arms, legs and fingers, loose joints, chest wall deformity, lens dislocation, aortic enlargement |
| Klinefelter syndrome (47,XXY) | Tall boys with long legs, small firm testes, breast development, delayed or incomplete puberty, learning difficulties |
| Sotos syndrome | Large head, overgrowth from birth, advanced bone age, learning difficulties |
| Beckwith-Wiedemann syndrome | Large birth weight, large tongue, abdominal wall defects, one side larger, raised risk of childhood tumors |
| Homocystinuria | Marfan-like build with lens dislocation, blood clots and learning difficulties |
Overgrowth of one body part
Excessive growth of one limb or one side (hemihypertrophy) can occur in Beckwith-Wiedemann syndrome, PIK3CA-related overgrowth spectrum (including Klippel-Trenaunay syndrome) and Proteus syndrome. Children with isolated hemihypertrophy may be offered regular abdominal ultrasounds in early childhood because of a slightly increased risk of kidney and liver tumors.
Localized "abnormal growths"
People also use "abnormal growth" to mean a lump. A bony bump on the big toe joint is most often a bunion or, if it is red and very painful, gout. Growths on the skin, such as keloids, skin tags or warts, are covered elsewhere and are not the same as overgrowth.
How excessive growth is assessed
- Accurate measurements of height, weight, head size, arm span and sitting height, plotted on a growth chart over time.
- Parents' heights to calculate the target range.
- Puberty staging and a full examination for features of syndromes.
- Bone age X-ray of the left hand and wrist, which shows how much growth remains.
- Blood tests: IGF-1 (a marker of growth hormone), thyroid function, sex hormones and LH/FSH.
- Glucose tolerance test with growth hormone levels to confirm acromegaly or gigantism.
- Pituitary MRI if growth hormone is high or early puberty is centrally driven.
- Genetic tests such as karyotype or gene panels when a syndrome is suspected.
- Eye exam and echocardiogram if Marfan syndrome is possible.
Treatment
Treatment targets the cause:
- Familial tall stature: reassurance; no treatment is needed.
- Precocious puberty: GnRH analog injections pause puberty until a more typical age.
- Pituitary tumor: surgery through the nose, with medicines (somatostatin analogs, pegvisomant) or radiotherapy if needed.
- Hyperthyroidism: antithyroid medicines, radioactive iodine or surgery.
- Marfan syndrome: regular heart scans, blood pressure medicines to protect the aorta, and surgery when the aorta widens.
- Klinefelter syndrome: testosterone replacement from puberty.
- Limb overgrowth: orthopedic treatment for leg length difference; targeted medicines for some PIK3CA-related conditions.
Hormone treatment to limit growth in very tall but healthy children is now rarely used.
Frequently asked questions
What causes excessive growth in a child?
Most tall children have tall parents and are healthy. Medical causes include early puberty, an overactive thyroid, excess growth hormone from a pituitary tumor, childhood obesity and genetic conditions such as Marfan, Klinefelter, Sotos and Beckwith-Wiedemann syndromes. A child crossing growth lines upward should be assessed.
What is the difference between gigantism and acromegaly?
Both are caused by too much growth hormone, usually from a pituitary tumor. Gigantism starts in childhood before the growth plates close, so the person becomes very tall. Acromegaly starts in adulthood, so height does not change but hands, feet, jaw and facial features enlarge.
Can adults have excessive growth?
Adults cannot grow taller once growth plates close. But excess growth hormone in acromegaly causes hands, feet, jaw, nose and tongue to keep enlarging. Rings that no longer fit, larger shoe sizes, and coarsening features in old photos are classic clues.
Is being very tall a health problem?
Usually not. Familial tall stature is normal. Tall stature becomes a concern when it comes with early puberty, unusually fast growth, features of a genetic syndrome, or symptoms such as headaches or vision changes. A pediatrician can sort this out with a growth chart and a few tests.
What is hemihypertrophy?
Hemihypertrophy means one side of the body, or one limb, grows larger than the other. It can be isolated or part of an overgrowth syndrome such as Beckwith-Wiedemann. Children with it may need regular checks, including belly ultrasounds, and treatment for leg length differences.
Sources
This guide was written from current patient and clinical guidance, including:
- Endocrine Society: Acromegaly clinical practice guideline
- Pediatric Endocrine Society: Tall stature patient information
- MedlinePlus: Gigantism; Precocious puberty; Acromegaly
- NHS: Acromegaly; Early or delayed puberty
- Marfan Foundation: What is Marfan syndrome