c'mon guys... GOOGLE!! Telogen Effluvium can occur when there is a significant physiological trauma. Excessive hair loss is noticeable about 3-4 months after this trauma, and can last for about 4-7 months. What causes this hair loss, is your body sending a larger than normal number of follicles into the state of telogen (resting). IF the factor that caused the trauma IS NOT removed, it can become chronic. If you're experiencing Telogen Effluvium from a certain medication, for example, and you DO NOT cease to take this medication, then you may experience it again. Some chronic Telogen Effluvium is unexplainable. This is rare however. Some people are more sensitive to experiencing Telogen Effluvium than others, and in certain people, once you experience the first time, it can become easier to trigger.