An overproduction of skin oil and irritation from the yeast malassezia causes an itchy scalp condition called dandruff.
Washing your hair too much or too little can cause an itchy scalp.
Thick patches of red skin and silvery scales on the scalp are caused by head lice.
Insects that live on people’s heads and feed on blood are called lice.
Tinea capitis is the name of a fungal infection of the scalp, also known as ringworm.