Isotretinoin-unresponsive acne as a sign of a congenital disorder: a case of 21-hydroxylase deficiency.

Acne is a multifactorial and common disorder among young people and a frequent reason for dermatology consultation. When moderate-to-severe acne is not responsive to conventional treatments, oral isotretinoin is a very effective solution. However, there are cases in which this treatment fails to produce the expected results. In this case, an 18-year-old male patient with acne, unresponsive to traditional acne therapies, experienced only a partial benefit from oral isotretinoin. Endocrinology consultation and hormonal work-up revealed androgen metabolism anomalies suggestive of a non-classical form of congenital adrenal hyperplasia due to 21-hydroxylase deficiency. In this case report, the authors discuss when to suspect, how to diagnose, and how to manage similar cases.