Paediatrics: Variants of normal puberty
These include premature thelarche and premature adrenarche. Neither condition is associated with pubertal activation of the hypothalamic–pituitary–gonadal axis.
Variants of normal puberty
- Isolated premature breast development occurring in the absence of any other signs of puberty.
- Typically, females present in infancy and usually by 2yrs of age.
- Breast development is due to the action of physiological or mild increases in the amounts of circulating oestrogen.
The clinical course is characterized by a waxing and waning of breast size, normal growth (height) rate, and the absence of any further sexual development. Breast development may be asymmetrical, and there is usually a resolution of any breast enlargement by age 4–5yrs.
The cause is unknown, but small increases in basal and stimulated serum FSH levels are usually observed. In contrast, LH levels remain suppressed in the prepubertal range. Ovarian follicle development is often observed, but no changes in ovarian or uterine size are seen. Serum oestradiol levels are increased when measured by sensitive assays, but typically within normal range by standard radioimmunoassay.
The condition is benign. Bone maturation, age of onset of menarche, and final adult height are not affected. Management is conservative with a re-evaluation of growth and puberty stage at 3–6-monthly intervals.
- An intermediate condition between premature thelarche and central precocious puberty.
- It represents a non-progressive form of early pubertal development.
Patients have evidence of breast development, increased growth rate, and advanced skeletal maturation on bone age assessment. There may also be evidence of ovarian enlargement and raised serum oestradiol levels. For most patients, the tempo of progression of pubertal development will be slow and they will have laboratory findings within the normal range for age. Management is usually conservative with a regular re-evaluation of growth and pubertal status at 3–6 monthly intervals. Decisions to treat (as for central PP) are based on height velocity and final height predictions.
Early-onset of pubertal adrenal androgen secretion is a common variation of normal pubertal development. Premature adrenarche is the result of premature secretion of androgens from the zona reticular is of the adrenal gland.
Children typically present with the premature appearance of androgen-dependent s sexual hair development (axillary hair, pubic hair, or both), acne, and axillary (body) odour.
- Patients may have mild acceleration in height velocity and a slight increase in BA.
- Laboratory investigations reveal an increase in serum DHEAS levels that are appropriate for the pubic hair stage rather than age.
- Serum concentrations of testosterone and 17-OH progesterone are normal.
When evaluating patients for premature adrenarche it is important to assess for clinical signs and symptoms that might indicate another cause of excess androgen production (e.g. adrenal tumour; congenital adrenal hyperplasia). The latter is characterized by signs of virilization, rapid growth rate, and significantly advanced bone age.
Premature adrenarche is a benign condition. The timing of onset of true puberty is normal and final adult height is unaffected. Management is conservative with reassurance after exclusion of other causes of adrenal androgen excess. Symptomatic treatment may be required if adrenarche is pronounced, particularly in females who may go on to develop features of ovarian hyperandrogenism and polycystic ovarian syndrome.