Nonclassical Congenital Adrenal Hyperplasia Presenting With Isolated Hirsutism in a Young Adult: A Case Report.

Congenital adrenal hyperplasia (CAH) comprises a group of autosomal recessive disorders caused by enzymatic deficiencies in adrenal steroidogenesis, resulting in impaired cortisol biosynthesis. These deficiencies may manifest as ambiguous genitalia in neonates, salt-wasting crises, or hirsutism in women. Although CAH is typically diagnosed in infancy or early childhood, nonclassical (late-onset) forms may present later in life. Nonclassical congenital adrenal hyperplasia (NCCAH), a milder variant of 21-hydroxylase deficiency, often manifests during adolescence or adulthood and remains an underrecognized cause of hyperandrogenism in females. We report the case of a 21-year-old woman who presented with isolated hirsutism in the absence of virilization or menstrual irregularities. Laboratory evaluation revealed elevated 17-hydroxyprogesterone and androgens, and the diagnosis was confirmed with an adrenocorticotropic hormone (ACTH) stimulation test. Imaging studies were unremarkable. Treatment was deferred due to the patient's regular menstrual cycles and her desire for fertility. This case underscores the importance of hormonal evaluation in isolated hirsutism and the role of ACTH stimulation testing in the definitive diagnosis of NCCAH.