Intrinsic factors

• Hormones

  • PCOS
  • Virilising tumours
  • Congenital adrenal hyperplasia
  • Increased cortisol (Cushing's syndrome)
  • Increased growth hormone (acromegaly)

• Medications

  • Topical and systemic steroids
  • Oral contraceptive pill (higher androgen content, progesterone-only pill)
  • Phenytoin
  • Barbiturates
  • Isoniazid
  • Ciclosporin
  • Lithium.

Extrinsic factors

• Oils/pomades
• Coal and tar
• Chlorinated phenols
• DDT and weed killers.