Causes of male androgen deficiency

Primary male androgen deficiency causes symptoms or signs of androgen deficiency, low serum testosterone concentration and elevated serum luteinising hormone (LH) concentration. It results from testicular disorders, including:

• Klinefelter syndrome¹
• cryptorchidism
• orchidectomy
• orchitis
• cytotoxic or radiation damage to the testes
• testicular torsion or trauma
• androgen synthesis inhibitors.

Central androgen deficiency causes symptoms or signs of androgen deficiency and low serum testosterone and LH concentrations. It results from hypothalamic or pituitary disorders, including hyperprolactinaemia.

• pituitary tumours
• pituitary surgery or radiotherapy
• haemochromatosis, which can cause iron deposition in the hypothalamus and pituitary
• hypophysitis
• idiopathic hypogonadotrophic hypogonadism (including Kallmann syndrome, notable for reduced or absent sense of smell²
• gonadotrophin-releasing hormone (GnRH) analogues.

Conditions to be distinguished from central androgen deficiency include:

• exogenous synthetic androgen use
• recent acute illness and convalescence
• functionally low testosterone concentrations.

Use of exogenous synthetic androgens may result in a biochemical picture that is similar to central androgen deficiency, but without the expected clinical signs of androgen deficiency; see History and examination.

Recent acute illness and convalescence can cause temporary hypothalamic–pituitary–testicular axis suppression.

Also consider the possibility of functionally low serum testosterone concentration , in which total serum testosterone concentration is usually only mildly reduced in men with comorbidities.