Tinea capitis (ringworm) affects an estimated 10 percent to 20 percent of susceptible children, and although the demographics are sketchy, telogen effluvium is the most common type of alopecia in both children and adults.
In telogen effluvium, there is a physiologic basis to the hair loss; something happens to interrupt the hair's normal growth cycle and to drive many or all of the hairs into the telogen phase.
Telogen Effluvium: Loss caused by physical or emotional stress, abnormal thyroid activity, medication, or hormonal fluctuations.
At any given time, roughly 15% of your total hair will be experiencing the telogen inactive phase of growth.
Excessive hair loss is called telogen effluvium, a condition that has various causes including pregnancy.