Response to treatment of congenital adrenal hyperplasia in infancy.

Nine infants with congenital adrenal hyperplasia were started on replacement doses of hydrocortisone (20.6-32.6 mg/m2/day) without receiving a high dose for an initial period first. Plasma adrenal steroid concentrations fell to acceptable levels by 3 months of age. Adequate biochemical control was maintained and satisfactory growth achieved even though the mean dose of hydrocortisone had been reduced to 15 mg/m2/day by the age of 3 years. Inadvertent overtreatment and growth suppression in infants with congenital adrenal hyperplasia may be avoided by using replacement doses from the start, and by permitting the relative dose of hydrocortisone to fall as the body surface area increases during the first year of life.