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HAIR-AN syndrome

Synonym(s) Hyperandrogenic-insulin resistant-acanthosis nigricans syndrome
Prevalence >1 / 1000
Inheritance -
Age of onset Adolescent
  • E28.2
  • C1963745
  • C537629
  • 10067378


HAIR-AN syndrome is a subphenotype of polycystic ovary syndrome (PCOS; see this term) and is characterized by hyperandrogenism, insulin resistance, and acanthosis nigricans. It is one of the most common causes of menstrual disorders, hyperandrogenic symptoms, and insulin resistance among young women.

It is not a rare disease. The annual incidence worldwide is estimated at around 5% of adolescent girls. Approximately 5-10% of females with hyperandrogenism, and up of 40% of adolescent patients with irregular periods, may have HAIR-AN syndrome.

Symptoms occur from adolescence, but diagnosis is often delayed until adulthood. Hyperandrogenism manifests as acne, slowly progressive hirsutism (Ferriman and Gallwey score of 8 or higher), and sometimes virilization including temporal balding, voice deepening, and clitoromegaly. Many patients have menstrual dysfunction, infrequent or absent ovulation, and polycystic ovaries. Insulin resistance may lead to obesity, numerous skin tags (achrochordons), and acanthosis nigricans. Acanthosis nigricans is characterized by the presence of velvety, verrucous, hyperpigmented skin, found most frequently on the back of the neck, axillae, and in other skin fold areas. HAIR-AN syndrome can cause acute psychological distress with morbidity, depression (24% of cases), and self-esteem problems. Due to insulin resistance, obesity, and menstrual dysfunction, patients have a significantly increased risk of type 2 diabetes mellitus and infertility.

Etiology is still unknown but the syndrome may be associated with mutations of the tyrosine kinase domain of the insulin receptor gene (INSR).

Diagnosis is based on the presence of the triad: hyperandrogenism, insulin resistance, and acanthosis nigricans. However, women with insulin resistance may not present with acanthosis nigricans. Fasting insulin levels, fasting glucose-to-insulin ratio, glucose challenge testing, and the euglycemic hyperinsulinemic clamp tests may be useful to confirm the diagnosis, but no solid consensus has been established so far.

Differential diagnoses include late-onset congenital adrenal hyperplasia (see this term), Cushing's syndrome (see this term), and ovarian and adrenal hormone producing tumors.

Management is multifactorial and includes weight loss, oral contraceptive pills, and antiandrogens (spironolactone, GnRH agonists, and flutamide, used in association with contraception). Treatments for insulin resistance, such as metformin, are controversial but are used frequently. Management should also include consideration of the potential psychological disorders.

Early diagnosis and treatment of HAIR-AN syndrome may improve the quality of life of patients. Undiagnosed and untreated insulin resistance is linked to long-term sequelae, such as coronary artery disease, hyperlipidemia, and type II diabetes. In adolescents, depression and potential suicidal behavior should be aggressively addressed.

Expert reviewer(s)

  • Pr Hatim OMAR

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