Transient scrotal hair growth in infancy

A male infant presented at 15 weeks of age having developed a number of dark coarse scrotal hairs during the preceding week (fig 1). There were no other signs of androgenisation and testes were of normal infant size. Investigations showed a testosterone concentration within the normal range at 3.2 nmol/l (age related reference range 0.03–6.14 nmol/l),1 and a normal urinary androgen profile. Serum cortisol, 17 hydroxy-progesterone, FSH, LH, thyroxine, and TSH levels were unremarkable. Subsequent linear growth was normal and by 7 months of age, the scrotal hair had disappeared. Transient isolated scrotal hair development starting at a few months of age has been reported in a total of 10 infants from various centres in the USA.2–5 To our knowledge this has not been reported from the UK. In seven cases spontaneous disappearance of scrotal hair occurred at between 8–15 months of age.2,5 In two cases it was “diminished” by 13 months and 21 months of age,4 and in the remaining case time of resolution was not stated.3 All were thoroughly investigated and no underlying pathological cause was found.